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1

Geological-structural models used in SR 97. Uncertainty analysis  

Energy Technology Data Exchange (ETDEWEB)

The uncertainty of geological-structural models was studied for the three sites in SR 97, called Aberg, Beberg and Ceberg. The evaluation covered both regional and site scale models, the emphasis being placed on fracture zones in the site scale. Uncertainty is a natural feature of all geoscientific investigations. It originates from measurements (errors in data, sampling limitations, scale variation) and conceptualisation (structural geometries and properties, ambiguous geometric or parametric solutions) to name the major ones. The structures of A-, B- and Ceberg are fracture zones of varying types. No major differences in the conceptualisation between the sites were noted. One source of uncertainty in the site models is the non-existence of fracture and zone information in the scale from 10 to 300 - 1000 m. At Aberg the development of the regional model has been performed very thoroughly. At the site scale one major source of uncertainty is that a clear definition of the target area is missing. Structures encountered in the boreholes are well explained and an interdisciplinary approach in interpretation have taken place. Beberg and Ceberg regional models contain relatively large uncertainties due to the investigation methodology and experience available at that time. In site scale six additional structures were proposed both to Beberg and Ceberg to variant analysis of these sites. Both sites include uncertainty in the form of many non-interpreted fractured sections along the boreholes. Statistical analysis gives high occurrences of structures for all three sites: typically 20 - 30 structures/km{sup 3}. Aberg has highest structural frequency, Beberg comes next and Ceberg has the lowest. The borehole configuration, orientations and surveying goals were inspected to find whether preferences or factors causing bias were present. Data from Aberg supports the conclusion that Aespoe sub volume would be an anomalously fractured, tectonised unit of its own. This means that the borehole investigations may not represent the site outside the covered volume. Finally five different uncertainty indices were calculated for regional and site scale, borehole data, representativity and structural knowledge. High uncertainty exists for all site volumes in terms of structural knowledge. Uncertainty in representativity is rather high at Aberg. Beberg and Ceberg has high uncertainty indices when regional scale models are concerned 30 refs, 36 figs, 8 tabs

Saksa, P.; Nummela, J. [FINTACT Oy (Finland)

1998-10-01

2

Analysis of effects of geological structures in rock driving by TBM  

Directory of Open Access Journals (Sweden)

Full Text Available Although mechanical properties belongs to important parameter for the excavation modelling, effect of geological structures on the rock massive fragmentation is often much higher than varying rock properties. This paper deals with the analysis of geological structures. It is focused on the schistosity orientation towards the tunnel azimuth. The aim is to define of schistosity effect on the penetration rate. It is a basis creating of fuzzy rules for the performance model full-profile tunnel boring machine

?udmila Tréfová

2006-12-01

3

Structural Geology and Geomechanics  

Science.gov (United States)

The teaching and research program, Structural Geology and Geomechanics at Stanford University, concentrates on brittle deformation in the earth's crust as well as fracturing and faulting of rocks under ductile conditions. Researchers can learn about the group's research which effectively unites field observations, laboratory experiments, and theoretical modeling. Scientists can learn about the program's software such as the Poly3Dinv which uses triangular dislocations to solve linear inverse problems. The site also publicizes the Stanford Rock Fracture Project, which researches rock fractures, crustal deformation, and fluid flow.

4

Teaching Resources in Structural Geology  

Science.gov (United States)

This portal provides access to an extensive selection of web-based teaching resources in structural geology. It features basic information on rock types, faults, folds, and other structures; virtual maps and field trips; and on strain and rheology. There is also a page of links to external sites on structural geology.

5

OpenStereo: Open Source, Cross-Platform Software for Structural Geology Analysis  

Science.gov (United States)

Free and open source software (FOSS) are increasingly seen as synonyms of innovation and progress. Freedom to run, copy, distribute, study, change and improve the software (through access to the source code) assure a high level of positive feedback between users and developers, which results in stable, secure and constantly updated systems. Several software packages for structural geology analysis are available to the user, with commercial licenses or that can be downloaded at no cost from the Internet. Some provide basic tools of stereographic projections such as plotting poles, great circles, density contouring, eigenvector analysis, data rotation etc, while others perform more specific tasks, such as paleostress or geotechnical/rock stability analysis. This variety also means a wide range of data formating for input, Graphical User Interface (GUI) design and graphic export format. The majority of packages is built for MS-Windows and even though there are packages for the UNIX-based MacOS, there aren't native packages for *nix (UNIX, Linux, BSD etc) Operating Systems (OS), forcing the users to run these programs with emulators or virtual machines. Those limitations lead us to develop OpenStereo, an open source, cross-platform software for stereographic projections and structural geology. The software is written in Python, a high-level, cross-platform programming language and the GUI is designed with wxPython, which provide a consistent look regardless the OS. Numeric operations (like matrix and linear algebra) are performed with the Numpy module and all graphic capabilities are provided by the Matplolib library, including on-screen plotting and graphic exporting to common desktop formats (emf, eps, ps, pdf, png, svg). Data input is done with simple ASCII text files, with values of dip direction and dip/plunge separated by spaces, tabs or commas. The user can open multiple file at the same time (or the same file more than once), and overlay different elements of each dataset (poles, great circles etc). The GUI shows the opened files in a tree structure, similar to “layers” of many illustration software, where the vertical order of the files in the tree reflects the drawing order of the selected elements. At this stage, the software performs plotting operations of poles to planes, lineations, great circles, density contours and rose diagrams. A set of statistics is calculated for each file and its eigenvalues and eigenvectors are used to suggest if the data is clustered about a mean value or distributed along a girdle. Modified Flinn, Triangular and histograms plots are also available. Next step of development will focus on tools as merging and rotation of datasets, possibility to save 'projects' and paleostress analysis. In its current state, OpenStereo requires Python, wxPython, Numpy and Matplotlib installed in the system. We recommend installing PythonXY or the Enthought Python Distribution on MS-Windows and MacOS machines, since all dependencies are provided. Most Linux distributions provide an easy way to install all dependencies through software repositories. OpenStereo is released under the GNU General Public License. Programmers willing to contribute are encouraged to contact the authors directly. FAPESP Grant #09/17675-5

Grohmann, C. H.; Campanha, G. A.

2010-12-01

6

Semi-automatic mapping of geological Structures using UAV-based photogrammetric data: An image analysis approach  

Science.gov (United States)

Recent advances in data acquisition technologies, such as Unmanned Aerial Vehicles (UAVs), have led to a growing interest in capturing high-resolution rock surface images. However, due to the large volumes of data that can be captured in a short flight, efficient analysis of this data brings new challenges, especially the time it takes to digitise maps and extract orientation data. We outline a semi-automated method that allows efficient mapping of geological faults using photogrammetric data of rock surfaces, which was generated from aerial photographs collected by a UAV. Our method harnesses advanced automated image analysis techniques and human data interaction to rapidly map structures and then calculate their dip and dip directions. Geological structures (faults, joints and fractures) are first detected from the primary photographic dataset and the equivalent three dimensional (3D) structures are then identified within a 3D surface model generated by structure from motion (SfM). From this information the location, dip and dip direction of the geological structures are calculated. A structure map generated by our semi-automated method obtained a recall rate of 79.8% when compared against a fault map produced using expert manual digitising and interpretation methods. The semi-automated structure map was produced in 10 min whereas the manual method took approximately 7 h. In addition, the dip and dip direction calculation, using our automated method, shows a mean±standard error of 1.9°±2.2° and 4.4°±2.6° respectively with field measurements. This shows the potential of using our semi-automated method for accurate and efficient mapping of geological structures, particularly from remote, inaccessible or hazardous sites.

Vasuki, Yathunanthan; Holden, Eun-Jung; Kovesi, Peter; Micklethwaite, Steven

2014-08-01

7

Structural Geology Musical Chairs  

Science.gov (United States)

This is a culminating activity designed to have students interpret structures in hand sample. Enough hand samples are chosen for the number of students in the class. Students are given a short amount of time to observe all samples. Music is started and they walk around the samples until the music stops. Each student must then present a description and interpretation of the hand sample in front of them.

Pignotta, Geoffrey

8

Geologic Photo Field Trips to View Rocks, Geologic Structures, and Landforms in Introductory Physical Geology  

Science.gov (United States)

Field photographs are used to enhance the instruction in teaching rocks, geologic structures, and landforms in Introductory Physical Geology lecture at East Carolina University. The field photographs are used to enhance the visual component of Physical Geology and are focused on rock outcrops (igneous, sedimentary, and metamorphic), geologic structures (faults and folds), and landforms (volcanic, weathering-erosion, mass wasting, fluvial, wind-desert, coastal, and karst).

Harper, Stephen B.

9

SoftStructure: Structural Geology on a PC  

Science.gov (United States)

SoftStructure is a package of more than 20 programs (most under DOS) for Quantitative Analysis in Structural Geology, including: MOHR, SHEAR, STRAIN, FRY, CALCITE_TWINS, STRESS_INVERSION, FOLTING, CRACK, ESHELBY, FAULT_GROWTH, and more. These programs are available for free for research and teaching purposes.

Others, Ze'Ev R.

10

Structure and data consistency of a GIS database for geological risk analysis in S. Miguel Island (Azores)  

Science.gov (United States)

The Geographic Information Systems (GIS) are becoming a major tool in the domain of geological hazard assessment and risk mitigation. When available, hazard and vulnerability data can easily be represented in a GIS and a great diversity of risk maps can be produced following the implementation of specific predicting models. A major difficulty for those that deal with GIS is to obtain high quality, well geo-referenced and validated data. This situation is particularly evident in the scope of risk analysis due to the diversity of data that need to be considered. In order to develop a coherent database for the geological risk analysis of the Azores archipelago it was decided to use the digital maps edited in 2001 by the Instituto Geográfico do Exército de Portugal (scale 1:25000), comprising altimetry, urban areas, roads and streams network. For the particular case of S. Miguel Island the information contained in these layers was revised and rectifications were made whenever needed. Moreover basic additional layers were added to the system, including counties and parishes administrative limits, agriculture and forested areas. For detailed studies all the edifices (e.g. houses, public buildings, monuments) are being individualized and characterized taking in account several parameters that can become crucial to assess their direct vulnerability to geological hazards (e.g. type of construction, number of floors, roof stability). Geological data obtained (1) through the interpretation of historical documents, (2) during recent fieldwork campaigns (e.g. mapping of volcanic centres and associated deposits, faults, dikes, soil degassing anomalies, landslides) and (3) by the existent monitoring networks (e.g. seismic, geodetic, fluid geochemistry) are also being digitised. The acquisition, storage and maintenance of all this information following the same criteria of quality are critical to guarantee the accuracy and consistency of the GIS database through time. In this work we notice the GIS-based methodologies aimed to assure the development of a GIS database directed to the geological risk analysis in S. Miguel Island. In a long-term programme the same strategy is being extended to the other Azorean islands.

Queiroz, G.; Goulart, C.; Gaspar, J. L.; Gomes, A.; Resendes, J. P.; Marques, R.; Gonçalves, P.; Silveira, D.; Valadão, P.

2003-04-01

11

Google Earth Exercises for Structural Geology  

Science.gov (United States)

We use these Google Earth Exercises (GEE) in the undergraduate structural geology course. Students construct a complete geologic map of each 'field area' outside of class; in class, the students display their map and discuss their observations, interpretations, assumptions, and reasoning. This exercise promotes discussion among the students, and also provides students with the opportunity to develop speaking skills, as well as 'on-your feet' reasoning and analysis. Mapping can be done digitally using graphic software such as Adobe IllustratorTM or using hard copy images and overhead transparencies. (Digital mapping requires that the students have knowledge of working with, and access, to a graphics program such as Adobe IllustratorTM). Students also draw stratigraphic columns and cross-sections as needed; and they determine a relative sequence of events for each 'field' area. Cross section lines are included in the .kmz (Google Earth) file (not on the map images). This allows the instructor to move cross-section locations as needed. We have 3-4 students display and discuss maps for each exercise (usually takes about 30-45 min.); we encourage student to question their classmates; with time, our encouragement becomes less necessary. We have students construct geologic maps on transparencies and display the maps via an overhear projector keeping the LCD projector free to run Google Earth. Students can use Google Earth (flying to specific locations, or zooming in and out, or viewing specific locations from different perspectives) during their presentation to illustrate or support their interpretation, and logic path that lead to that interpretation to the class. This provides the opportunity for students to see how different people interpret the same area; they also learn that although each maps is different, each map tells a similar story; that is first-order relationships emerge from the family of maps constructed by their fellow classmates. After each discussion, all of the students display their maps on a side table in the classroom, providing the students with the opportunity to compare all of the maps of the same area. As a result they clearly see that all maps are different, yet each can be valid, and they also see how others handled both geologic relations, and, at a more basic level, clarity and neatness in presentation. As the semester progresses we see a sharp increase in the quality of the maps, both geologically and in terms of clarity and neatness, likely a direct result of students both viewing their classmates maps, and having their maps viewed by classmates. Peer pressure can be a wonderful learning tool. Each exercise focuses on a different area. An individual exercise or any combination of exercises maybe used at the instructor's discretion to compliment topics in either lecture or lab. The exercises, as presented, are ordered in such a way that they take the student progressively from relatively straightforward map areas to increasing complicated map areas. We begin the geologic mapping sequence using a Venus mapping exercise available on the SERC site http://serc.carleton.edu/NAGTWorkshops/structure04/activities/3875.html in order to get the students to feel comfortable identifying and delineating patterns; we develop concepts about material units versus structural elements (and in some cases primary verses secondary structures; please see the Venus exercise for the range of students goals, which we do not repeat here). The first Google Earth Exercise, (GEE1) follows the SERC exercise 'Visualizing Inclined Contacts' by Barbara Tewksbury http://serc.carleton.edu/NAGTWorkshops/structure/visualizing_inclined.html . Our GEE1 exercise is included below with all credit to Barbara Tewksbury. Subsequent exercises (GEE2, GEE3, etc.) include: faults and topographic interactions; folds and topographic interactions; faults and crosscutting dikes; refolded folds. These exercises may be used in any order and/or positioning within a course. We find that both the repetition of GEE exercises, and the progression of incre

Dyess, Jonathan

12

Logic tree-based GIS inference of geologic structure  

Science.gov (United States)

We describe the concept for a logic-tree based geographic information system (GIS) that can infer subsurface geology and material properties using geoinformatics concepts. A proof-of-concept system was devised and tested integrating the capabilities of traditional terrain- and image-analysis procedures with a GIS to manipulate geospatial data. Structured logic trees were developed to guide an analyst through an interactive, geologic analysis based on querying and mentoring heuristic logic. The hypotheses were that a GIS can be programmed to 1) follow the fundamental logic sequence developed for traditional terrain- and image analysis procedures; 2) augment that sequence with correlative geospatial data from a variety of sources; and 3) integrate the inferences and data to develop "best-guess" estimates. We also developed a method to estimate depth to bedrock, and expanded an existing method to determine water table depth. Blind evaluations indicate that an analyst can infer the correct geologic conditions 70-80% of the time using this method. This geologic analysis technique can be applied wherever an estimate of subsurface geology is needed. We apply the results of our geological analysis to the prediction of local site specific seismic propagation. Comparisons are made with synthetic seismograms computed from a limited set of geological vignettes.

Ryerson, Charles C.; Anderson, Thomas S.

2007-10-01

13

The need for the geologic hazard analysis  

International Nuclear Information System (INIS)

The parameters which are considered in the hazard analysis associated with the movements of the Earth Crust are considered. These movements are classified as: fast movements or seismic movements, which are produced in a certain geologic moment at a speed measured in cm/sg, and slow movements or secular movements, which take place within a long span of time at a speed measured by cm/year. The relations space/time are established after Poisson and Gumbel's probabilistic models. Their application is analyzed according to the structural gradient fields, which fall within Matteron's geostatistics studies. These statistic criteria should be analyzed or checked up in each geo-tectonic environment. This allows the definition of neotectonic and seismogenetic zones, because it is only in these zones where the probabilistic or deterministic criteria can be applied to evaluate the hazard and vulnerability, that is, to know the geologic hazard of every ''Uniform'' piece of the Earth Crust. (author)

14

Formation of secondary phases during deep geological final disposal of research reactor fuel elements. Structure and phase analysis  

International Nuclear Information System (INIS)

For the assessment of a confident und sustainable final disposal of high level radioactive waste - fuel elements of german research reactors also account for such waste - in suitable, deep geological facilities, processes of the alteration of the disposed of waste and therefore the formation of the corrosion products, i. e. secondary phases must be well understood considering an accident scenario of a potential water inflow. In order to obtain secondary phases non-irradiated research reactor fuel elements (FR-BE) consisting of UAlx-Al were subjected to magnesium chloride rich brine (brine 2, salt repository) and to clay pore solution, respectively and furthermore of the type U3Si2-Al were solely subjected to magnesium chloride rich brine. Considering environmental aspects of final repositories the test conditions of the corrosion experiments were adjusted in a way that the temperature was kept constant at 90 C and a reducing anaerobic environment was ensured. As major objective of this research secondary phases, obtained from the autoclave experiments after appropriate processing and grain size separation have been identified and quantified. Powder X-ray diffraction (PXRD) and the application of Rietveld refinement methods allowed the identification of the corrosion products and a quantitative assessment of crystalline and amorphous contents. Scanning and transmission electron microscopy were additionally applied as a complementary method for the characterisation of the secondary phases. The qualitative phase analysis of the preprocessed secondary phases of the systems UAlx-Al and U3Si2-Al in brine 2 shows many similarities. Lesukite - an aluminium chloro hydrate - was observed for the first time considering the given experimental conditions. Further on different layered structures of the LDH type, iron oxyhydroxide and possibly iron chlorides, uncorroded residues of nuclear fuel and elementary iron were identified as well. Depending on preceding preparation procedures of the secondary phases the phase mixture resulted in different constituents. By preparation in water the stable phases obtained were aluminium hydroxides and not lesukite. Crystalline phases containing silicon were solely observed in the system U3Si2-Al in brine 2 being prepared with water. Contrary to these observations the system UAlx-Al in Mont Terri solution (clay pore water) qualitatively exhibits distinct different phase contents. Goethite, gypsum, hemi hydrate (bassanite), and accessory hematite were the only crystalline phases observed. Additionally aluminium and UAl4 as residues of nuclear fuel were also found. Considering the quantification of the brine 2 systems many common observations could be made. With respect to the corrosion products of UAlx-Al und U3Si2-Al prepared with isopropanol, lesukite and LDH compounds are the most abundant phases. The amorphous content, elemental iron and uncorroded residues of the nuclear fuel are mainly enriched in the coarse grain size fraction > 63 ?m. The water treatment of the secondary phases resulted in much less yield of solids. Quantitatively aluminium hydroxides exhibited the highest abundance. Clear differences could be observed in the system UAlx-Al in Mont Terri solution in view of the fact that the amorphous phases show the highest content of the corrosion products. The secondary phases could retain radioactive isotopes on the one hand by in situ formation and on the other hand by additionally being placed into stock as backfill, respectively. As special objective for assessing the potential of retention the amount of incorporation of europium into the crystal lattice of LDH compounds has also been investigated. Up to 20 mole percent considering the amount of aluminium were substituted by inactive europium acting as a trivalent simulant homologue for actinides. The refinement of the lattice parameters clearly indicated a linear relationship between the increase of the europium amount and the increase of the lattice parameters. The capacity of the incorporation of repository relevant isotopes in th

15

Geologic analysis of Devonian Shale cores  

Energy Technology Data Exchange (ETDEWEB)

Cleveland Cliffs Iron Company was awarded a DOE contract in December 1977 for field retrieval and laboratory analysis of cores from the Devonian shales of the following eleven states: Michigan, Illinois, Indiana, Ohio, New York, Pennsylvania, West Virginia, Maryland, Kentucky, Tennessee and Virginia. The purpose of this project is to explore these areas to determine the amount of natural gas being produced from the Devonian shales. The physical properties testing of the rock specimens were performed under subcontract at Michigan Technological University (MTU). The study also included LANDSAT information, geochemical research, structural sedimentary and tectonic data. Following the introduction, and background of the project this report covers the following: field retrieval procedures; laboratory procedures; geologic analysis (by state); references and appendices. (ATT)

none,

1982-02-01

16

Inner thermal resonance in thermoelastic geological structures  

Science.gov (United States)

When investigating heterogeneous media such as composite materials or geological structures, it is convenient to replace them by macroscopic equivalent media, which simplifies computations a lot. In the paper, we look for the equivalent macroscopic model for describing seismic wave propagation and transient heat transfers in thermoelastic periodic geological structures made of rock or soil. We follow the route described in Auriault (2012), to investigating thermoelastic composite media. We use the method of multi-scale asymptotic expansions. By estimating the dimensionless numbers in the momentum and energy balances, we show that an equivalent macroscopic model exists for describing seismic waves at very low frequencies only. The model then shows a damping which is due to thermal resonance at the heterogeneity scale. At higher frequencies, such an equivalent macroscopic model does not exist. Macroscopic models for describing transient heat transfers do not exist.

Auriault, Jean-Louis

2014-10-01

17

Applied Structural Geology – Case Studies of Underground Constructions and Rockslides  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An understanding of the structural elements in the sub-surface is of great importance when establishing new constructions in bedrock, or surveying areas prone to rockslides. In this thesis the focus has been on combining methods within geology, structural geology, geophysics and engineering geology to reach an interdisciplinary understanding and predict sub-surface structures. Geological feasibility studies for tunnel projects are a good aid to foresee areas of construction pro...

Ganerød, Guri Venvik

2008-01-01

18

Three-dimensional Geological and Geo-mechanical Modelling of Repositories for Nuclear Waste Disposal in Deep Geological Structures  

Energy Technology Data Exchange (ETDEWEB)

To prove the suitability and safety of underground structures for the disposal of radioactive waste extensive geo-scientific research and development has been carried out by BGR over the last decades. Basic steps of the safety analysis are the geological modelling of the entire structure including the host rock, the overburden and the repository geometry as well as the geo-mechanical modelling taking into account the 3-D modelling of the underground structure. The geological models are generated using the special-construction openGEO{sup TM} code to improve the visualisation an d interpretation of the geological data basis, e.g. borehole, mine, and geophysical data. For the geo-mechanical analysis the new JIFE finite-element code has been used to consider large 3-D structures with complex inelastic material behaviour. To establish the finite-element models needed for stability and integrity calculations, the geological models are simplified with respect to homogenous rock layers with uniform material behaviour. The modelling results are basic values for the evaluation of the stability of the repository mine and the long-term integrity of the geological barrier. As an example of application, the results of geological and geo-mechanical investigations of the Morsleben repository based on 3-D modelling are presented. (authors)

Fahland, Sandra; Hofmann, Michael; Bornemann, Otto; Heusermann, Stefan [Federal Institute for Geosciences and Natural Resources, Stilleweg 2, D-30655-Hannover (Germany)

2008-07-01

19

Three-dimensional Geological and Geo-mechanical Modelling of Repositories for Nuclear Waste Disposal in Deep Geological Structures  

International Nuclear Information System (INIS)

To prove the suitability and safety of underground structures for the disposal of radioactive waste extensive geo-scientific research and development has been carried out by BGR over the last decades. Basic steps of the safety analysis are the geological modelling of the entire structure including the host rock, the overburden and the repository geometry as well as the geo-mechanical modelling taking into account the 3-D modelling of the underground structure. The geological models are generated using the special-construction openGEOTM code to improve the visualisation an d interpretation of the geological data basis, e.g. borehole, mine, and geophysical data. For the geo-mechanical analysis the new JIFE finite-element code has been used to consider large 3-D structures with complex inelastic material behaviour. To establish the finite-element models needed for stability and integrity calculations, the geological models are simplified with respect to homogenous rock layers with uniform material behaviour. The modelling results are basic values for the evaluation of the stability of the repository mine and the long-term integrity of the geological barrier. As an example of application, the results of geological and geo-mechanical investigations of the Morsleben repository based on 3-D modelling are presented. (authors)

20

Piaui basin, a Jambalaya of geologic structures  

Energy Technology Data Exchange (ETDEWEB)

Although the Piaui basin was the last of the Brazilian equatorial marginal basins to be studied in detail, it is the one that presents the most fascinating structural geology of them all. The superposition of two major tectonic events, quite distinct in nature (rifting and wrenching), produced an abundance and diversity of geologic structures unparalleled by any other Brazilian basin. The first tectonic event, the rift-stage (early Aptian), created the basin through a series of normal faults predominantly oriented N40/sup 0/-45/sup 0/E in the western part, and N75/sup 0/-85/sup 0/E in the eastern part. Clastic continental sediments constitute the rift depositional sequence. Continental drifting followed (late Aptian-early Cenomanian), and a thick clastic sequence of transitional to marine sediments was deposited. Wrenching was already taking place, but on a small scale. During the middle Cenomanian (approx. = 95-93 m.y.B.P.) the separation between South America and Africa in this area changed from north-south to east-west along the oceanic Romanche fracture zone. Shear stresses developed. The right-lateral motion, the large bend in the Parnaiba platform, and the different average trends of rift faults from west to east resulted in convergent wrenching. Transpression was greatly enhanced. Rift faults were reactivated as dextral strike-slip faults. Synthetic (N65/sup 0/-70/sup 0/W) and antithetic (N20/sup 0/W and NS) strike-slip faults were formed. Flower structures occurred along the fault trends. Abundant en echelen folds and shale ridges (N20/sup 0/E) were created. By the time wrenching ceased, a transpressive belt of significant dimensions had emerged in the Piaui basin. Sedimentation resumed in the area during the Oligocene-Miocene.

Zalan, P.V.

1985-02-01

 
 
 
 
21

Structural effects of C60+ bombardment on various natural mineral samples-Application to analysis of organic phases in geological samples  

International Nuclear Information System (INIS)

Organic phases trapped inside natural mineral samples are of considerable interest in astrobiology, geochemistry and geobiology. Examples of such organic phases are microfossils, kerogen and oil. Information about these phases is usually retrieved through bulk crushing of the rock which means both a risk of contamination and that the composition and spatial distribution of the organics to its host mineral is lost. An attractive of way to retrieve information about the organics in the rock is depth profiling using a focused ion beam. Recently, it was shown that it is possible to obtain detailed mass spectrometric information from oil-bearing fluid inclusions, i.e. small amounts of oil trapped inside a mineral matrix, using ToF-SIMS. Using a 10 keV C60+ sputter beam and a 25 keV Bi3+ analysis beam, oil-bearing inclusions in different minerals were opened and analysed individually. However, sputtering with a C60+ beam also induced other changes to the mineral surface, such as formation of topographic features and carbon deposition. In this paper, the cause of these changes is explored and the consequences of the sputter-induced features on the analysis of organic phases in natural mineral samples (quartz, calcite and fluorite) in general and fluid inclusions in particular are discussed. The dominating topographical features that were observed when a several micrometers deep crater is sputtered with 10 keV C60+ ions on a natural mineral surface are conical-shaped and ridge-like structures that may rise several micrometers, pointing in the direction of the incident C60+ ion beam, on an otherwise flat crater bottom. The sputter-induced structures were found to appear at places with different chemistry than the host mineral, including other minerals phases and fluid inclusions, while structural defects in the host material, such as polishing marks or scratches, did not necessarily result in sputter-induced structures. The ridge-like structures were often covered by a thick layer of deposited carbon. Despite the appearance of the sputter-induced structures and carbon deposition, most oil-bearing inclusions could successfully be opened and analysed. However, smaller inclusion (60, carbon deposition, topography, mineral, fluid inclusions, geological samples, depth profiling.

22

Relationship between hypocentral distribution and geological structure in the Horonobe area, northern Hokkaido, Japan  

International Nuclear Information System (INIS)

In this paper, we discuss the relationship between the accurate hypocentral distribution and three-dimensional (3-D) geological structure in and around the Horonobe area in northern Hokkaido, Japan. The multiplet-clustering analysis was applied to the 421 micro-earthquakes which occurred from 1 September, 2003 to 30 September, 2007. The 3-D geological structure model was mainly constructed from previous seismic reflection profiles and borehole data. As a result of this analysis, although with slight differences in depth between them, the hypocenters were found to be distributed in the NNW-SSE direction and become deeper from the west toward the east. The distributed pattern of the hypocenters is similar to that of the geological structure. These results indicate that the hypocentral distribution may represent existence of active zone related to the geological structure, and provide effective information which can contribute to establishing methods for estimating the future evolution of the geological environment. (author)

23

Fracture analysis for engineering geological utilization  

Energy Technology Data Exchange (ETDEWEB)

The problem of geological hazards (earthquakes) and water or thermal resources urges us to understand the regional tectonic setting or recent tectonics. The Uisong Subbasin is located in one of the seismicity zones in Korea. Because the reactivity of the Gaeum Fault System is an important problem focussing on these faults, we studied their whole extension and timing of faulting in terms of tectonics. Fault tectonic analysis is so effective as to easily reconstruct the tectonic sequence and each stress state at each site, eventually in a region. One can get insights for faulting timing in terms of the restored tectonic sequence, and discriminating the active faults or the faults active in the last (present) tectonics. Examining the filling materials in tension gashes, one can get raw knowledge regarding the thermal states at each site. For this study, we first analyzed the topographic textures (lineament, drainage and circular structures) on the relief map produced based on the topographic maps of 1:100,000 scale. Through investigations of susceptible area along the faults, their existence and movement modes were studied, and we can get information about movement history and whole extension of the faults belonging to the WNW-ESE trending Gaeum Fault System. In order to reconstruct the tectonic sequence, we measured fault slip data, tension gashes and dikes, from which fault populations were classified and stress (and thermal) states were determined. Seven compressional tectonic events and six extensional events were reconstructed. Because coaxial events partially coexisted, we bundled these events in one, finally we get seven tectonic events. Determining the types of minerals filling the tension gashes, we suggested the possibility of investigation of geothermal resources with less efforts. (author). 162 refs., 14 tabs., 51 figs.

Choi, H.I.; Choi, P.Y.; Hong, S.H.; Chi, K.H.; Kim, J.Y.; Lee, S.R.; Lee, S.G.; Park, D.W.; Han, J.G. [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1997-12-01

24

Application of reactor activation analysis to hydrogeology and geology  

International Nuclear Information System (INIS)

Instrumental reactor activation analysis applied to hydrogeological and geological investigations conducted at the Department of Radiometry of the Geological Techniques Research and Development Centre is discussed. Used instrumentation and analytical techniques are described. (author)

25

Improvement of seismic imaging of complex geologic structures  

Energy Technology Data Exchange (ETDEWEB)

Successful imaging of complex geologic structures by pre-stack depth migration requires a correct velocity model of the subsurface. In recent years, it has been proposed to use pre-stack depth migration of the cube of pre-stack depth migrated images and the subsequent use of the interpretation for velocity model update. However, in complex geologic structures, pre-stack depth migration does not yield results of sufficient quality for interpretation. We therefore propose a new wave-field imaging technique based on linearized inversion using the paraxial approximation of the wave equation. Using this technique we can remove the artifacts contaminating the individual depth images by integrating a priori information in the inverse problem. The application of the method to synthetic and real data shows that it allows us to largely improve the quality of the depth images at reasonable cost.We thus obtain an interpretable cube of depth images that makes migration velocity analysis feasible in complex structures. In 3D, due to the size of the problem there is still a large interest in using post stack techniques for velocity model determination. The quality of the results of such techniques relies on the quality of the stacking process. Classical data stacking techniques rely on simplifications that are not valid anymore in case of complex geologic structures. We propose a data stacking technique based on depth domain stacking after pre-stack depth migration, followed by explosive reflector modeling, to obtain the stacked seismic data. This method which is totally automatic yield 3 D stacked data that are suitable for 3D post stack velocity determination techniques.

Duquet, B.

1996-04-11

26

Geologic Structures in Crater Walls on Vesta  

Science.gov (United States)

The Framing Camera (FC) on the Dawn spacecraft has imaged most of the illuminated surface of Vesta with a resolution of apporpx. 20 m/pixel through different wavelength filters that allow for identification of lithologic units. The Visible and Infrared Mapping Spectrometer (VIR) has imaged the surface at lower spatial resolution but high spectral resolution from 0.25 to 5 micron that allows for detailed mineralogical interpretation. The FC has imaged geologic structures in the walls of fresh craters and on scarps on the margin of the Rheasilvia basin that consist of cliff-forming, competent units, either as blocks or semi-continuous layers, hundreds of m to km below the rims. Different units have different albedos, FC color ratios and VIR spectral characteristics, and different units can be juxtaposed in individual craters. We will describe different examples of these competent units and present preliminary interpretations of the structures. A common occurrence is of blocks several hundred m in size of high albedo (bright) and low albedo (dark) materials protruding from crater walls. In many examples, dark material deposits lie below coherent bright material blocks. In FC Clementine color ratios, bright material is green indicating deeper 1 m pyroxene absorption band. VIR spectra show these to have deeper and wider 1 and 2 micron pyroxene absorption bands than the average vestan surface. The associated dark material has subdued pyroxene absorption features compared to the average vestan surface. Some dark material deposits are consistent with mixtures of HED materials with carbonaceous chondrites. This would indicate that some dark material deposits in crater walls are megabreccia blocks. The same would hold for bright material blocks found above them. Thus, these are not intact crustal units. Marcia crater is atypical in that the dark material forms a semi-continuous, thin layer immediately below bright material. Bright material occurs as one or more layers. In one region, there is an apparent angular unconformity between the bright material and the dark material where bright material layers appear to be truncated against the underlying dark layer. One crater within the Rheasilvia basin contains two distinct types of bright materials outcropping on its walls, one like that found elsewhere on Vesta and the other an anomalous block 200 m across. This material has the highest albedo; almost twice that of the vestan average. Unlike all other bright materials, this block has a subdued 1 micron pyroxene absorption band in FC color ratios. These data indicate that this block represents a distinct vestan lithology that is rarely exposed.

Mittlefehldt, David W.; Beck, A. W.; Ammannito, E.; Carsenty, U.; DeSanctis, M. C.; LeCorre, L.; McCoy, T. J.; Reddy, V.; Schroeder, S. E.

2012-01-01

27

Neutron activation analysis of geological material  

International Nuclear Information System (INIS)

In neutron activation analysis the precision and accuracy of results are often misleading, since only the statistical errors which accompany the measuring of radioactivity are taken into consideration. Several other factors can, however, also influence precision and accuracy. It was found that a geological sample was contaminated with the construction material of the mill in which it had been pulverised. Several geometrical differences which could possibly play a role were also investigated. Impurities in the irradiation containers affect the determination of some elements in the samples; the contamination materials in quarts irradiation tubes were determined. The flux gradients which may effect the relative activities of the samples and standards were measured. Suitable standards are necessary to ensure accurate analyses of geological material. Available natural standards were critically evaluated and several methods were investigated by which synthetic standards may be prepared. In order to accurately determine gallium, lanthanum and samarium by means of neutron activation analysis, sodium first had to be removed. After irradiation the sample was dissolved in a mixture of acids and the soidium absorbed from the solution on a hydrated antimony pentoxide column. Gallium, lanthanum and samarium activities were measured by means of precision gamma-spectrometry

28

The structural geology of the High Central Zagros revisited (Iran)  

Energy Technology Data Exchange (ETDEWEB)

The main purpose of this study in the High Central Zagros area near the townships of Lordegan and Yasuj was to investigate the nature of the High Zagros Fault (HZF) and the structural styles in the adjacent foreland. A second task was to determine whether the prolific petroleum plays productive further out in the Zagros Foreland would extend into this study area and if new petroleum plays could be recognized. Two selected cross-sections across and one just behind the HZF provide evidence for its overthrust nature. In some places the HZF exhibits a low-angle thrust plane, locally with a substantial amount of thrusting over the foreland. The interpretation is based on surface geological mapping, available well data, remote sensing from satellite data, aeromagnetic and high resolution gravimetry data, magnetotelluric, WARRP (wide angle reflection refraction profiling) and reflection seismic data. The integration of this unique set of newly acquired geophysical data complements recently published paper, which were based more on surface geology and rather limited subsurface data. The data were integrated to construct a regional balanced cross-section and to develop structural petroleum play concepts for the area investigated. Play potential may exist both in the overthrust terrain of the High Zagros as well as in the subthrust. Analysis of the width of the surface anticlines (or more precisely: their frequency) gives a first indication of the depth of the decollement plane. Within the adjacent Zagros Foreland evidence was found for the presence of multiple detachment planes above the ubiquitous deep Hormuz level, i.e. at the level of the Kazgdumi and the Pabdeh-Gurpi Formations. These intermediate decollement planes are thought to be responsible for the generation of deeper structural plays unrelated to the structuring that can be observed at the surface. (author)

Bosold, A.; Schwarzhans, W. [RWE Dea AG, Hamburg (Germany); Julapour, A.; Ashrafzadeh, A.R.; Ehsani, S.M. [NIOC 8th Central Building, Teheran (Iran)

2005-07-01

29

Initial phases for the development of a Structural Geology database  

Science.gov (United States)

We are at the beginning stages of developing a Data System for Structural Geology and Tectonics (SG&T). This activity is prompted by the necessity of reporting our data from government-funded projects and the lack of any existing database. SG&T data is complex for a variety of reasons, including the wide range of temporal and spatial scales (many orders of magnitude each), the complex three-dimensional geometry of some geological structures, inherent spatial nature of the data, and the difficulty of making temporal inferences from spatial observations. To successful implement the step of developing a SG&T data system, we must simultaneously solve three problems: 1) How to digitize SG&T data; 2) How to design a software system that is applicable; and 3) How to construct a very flexible user interface. To address the first problem, we introduce the "Spot" concept, which allows tracking of hierarchical and spatial relations between structures at all scales, and will link map scale, mesoscale, and laboratory scale data. A Spot, in this sense, is analogous to the beam size of analytical equipment used for in situ analysis of rocks; it is the size over which a measurement or quantity is applicable. A Spot can be a single measurement, an aggregation of individual measurements, or even establish relationships between numerous other Spots. We propose to implement both a Spot and a more traditional Mapping mode for data input. The final challenge is to construct a user interface that is intuitive, open source, and spans as many operating systems and devices as possible. For these reasons, we propose to develop a web-application that can run in both a connected (on the internet) and disconnected mode. Our hope is to have extensive and international community input into the data system development process.

Tikoff, Basil; Babaie, Hassan; Clark, Ryan; Newman, Juile; Walker, Doug

2014-05-01

30

Integrating structural geological data into the inverse modelling framework of iTOUGH2  

Science.gov (United States)

The validity of subsurface flow simulations strongly depends on the accuracy of relevant rock property values and their distribution in space. In realistic simulations, this spatial distribution is based on two geological considerations: (1) the subsurface structural setting, and (2) smaller-scale heterogeneity within a hydrostratigraphic unit. Both aspects are subject to uncertainty, whereas techniques to address heterogeneity are well established, no general method exists to evaluate the influence of structural uncertainties. We present a method to include structural geological data (e.g. observations of geological contacts and faults) directly into an inversion framework, with the aim of enabling the inversion routine to adapt a full 3-D geological model with a set of geological parameters. In order to achieve this aim, we use a set of Python modules to combine several pre-existing codes into one workflow, to facilitate the consideration of a structural model in the typical model evaluation steps of sensitivity analysis, parameter estimation, and uncertainty propagation analysis. In a synthetic study, we then test the application of these three steps to analyse CO2 injection into an anticlinal structure with the potential of leakage through a fault zone. We consider several parts of the structural setting as uncertain, most importantly the position of the fault zone. We then evaluate (1) how sensitive CO2 arriving in several observation wells would be with respect to the geological parameters, (2) if it would be possible to determine the leak location from observations in shallow wells, and (3) how parametric uncertainty affects the expected CO2 leakage amount. In all these cases, our main focus is to consider the influence of the primary geological data on model outputs. We demonstrate that the integration of structural data into the iTOUGH2 framework enables the inversion routines to adapt the geological model, i.e. to re-generate the entire structural model based on changes in several sensitive geological parameters. Our workflow is a step towards a combined analysis of uncertainties not only in local heterogeneities but in the structural setting as well, for a more complete integration of geological knowledge into conceptual and numerical models.

Wellmann, J. Florian; Finsterle, Stefan; Croucher, Adrian

2014-04-01

31

An analysis of fracture trace patterns in areas of flat-lying sedimentary rocks for the detection of buried geologic structure. [Kansas and Texas  

Science.gov (United States)

Two study areas in a cratonic platform underlain by flat-lying sedimentary rocks were analyzed to determine if a quantitative relationship exists between fracture trace patterns and their frequency distributions and subsurface structural closures which might contain petroleum. Fracture trace lengths and frequency (number of fracture traces per unit area) were analyzed by trend surface analysis and length frequency distributions also were compared to a standard Gaussian distribution. Composite rose diagrams of fracture traces were analyzed using a multivariate analysis method which grouped or clustered the rose diagrams and their respective areas on the basis of the behavior of the rays of the rose diagram. Analysis indicates that the lengths of fracture traces are log-normally distributed according to the mapping technique used. Fracture trace frequency appeared higher on the flanks of active structures and lower around passive reef structures. Fracture trace log-mean lengths were shorter over several types of structures, perhaps due to increased fracturing and subsequent erosion. Analysis of rose diagrams using a multivariate technique indicated lithology as the primary control for the lower grouping levels. Groupings at higher levels indicated that areas overlying active structures may be isolated from their neighbors by this technique while passive structures showed no differences which could be isolated.

Podwysocki, M. H.

1974-01-01

32

Geological structure and geochemistry controlling radon in soil gas  

International Nuclear Information System (INIS)

Geological factors causing radon anomalies are either geochemical/petrophysical (controlling the diffusive 222Rn and 220Rn potential), or structural (controlling the advective 222Rn component), or both. While geochemical anomalies normally are easily explained and rather stable in time, structural anomalies often show fluctuations and interpretation of their origin can be very intricate. Geology-based techniques for detecting and mapping previously unrecognised areas of high radon risk have been developed with case studies in the Cenozoic Neuwied Basin of the Middle Rhine region and in the Paleozoic crystalline basement rocks of Eastern Bavaria in Southern Oberpfalz, Germany. (author)

33

Deep geological disposal system development; mechanical structural stability analysis of spent nuclear fuel disposal canister under the internal/external pressure variation  

Energy Technology Data Exchange (ETDEWEB)

This work constitutes a summary of the research and development work made for the design and dimensioning of the canister for nuclear fuel disposal. Since the spent nuclear fuel disposal emits high temperature heats and much radiation, its careful treatment is required. For that, a long term(usually 10,000 years) safe repository for spent fuel disposal should be securred. Usually this repository is expected to locate at a depth of 500m underground. The canister construction type introduced here is a solid structure with a cast iron insert and a corrosion resistant overpack, which is designed for spent nuclear fuel disposal in a deep repository in the crystalline bedrock, which entails an evenly distributed load of hydrostatic pressure from undergroundwater and high pressure from swelling of bentonite buffer. Hence, the canister must be designed to withstand these high pressure loads. Many design variables may affect the structural strength of the canister. In this study, among those variables array type of inner baskets and thicknesses of outer shell and lid and bottom are tried to be determined through the mechanical linear structural analysis, thicknesses of outer shell is determined through the nonlinear structural analysis, and the bentonite buffer analysis for the rock movement is conducted through the of nonlinear structural analysis Also the thermal stress effect is computed for the cast iron insert. The canister types studied here are one for PWR fuel and another for CANDU fuel. 23 refs., 60 figs., 23 tabs. (Author)

Kwen, Y. J.; Kang, S. W.; Ha, Z. Y. [Hongik University, Seoul (Korea)

2001-04-01

34

Geological Structures As Reflection of Mantle Convection and Plumes  

Science.gov (United States)

The origin and evolution of geological structures could be a clue for understanding of crust-mantle interaction. For simulation of geological processes and geological struc- tures evolution in connection with deep mantle movements all possible geological- geophysical data were combined and analysed and the mechanical-mathematical mod- els of different rheology were used. Interpretation of petrological, geological, geother- mal and geophysical data was made also on the base of deep drilling and geotransects. Mantle activity of different scale can be reflected in surface dynamics. So on the base- ment of super plume can arise instability of smaller scale (diapirs). As plume is re- sponsible for whole Alpine belt activization as diapirs are connected with evolution of the belt sedimentary basins and rifts. The next problems were considered: form- ing and evolution of sedimentary basins, geothermal evolution of sedimentary cover, interaction of changeable sedimentary cover with crust and mantle lithosphere, re- construction of deep mantle motions by movements of basement surface, simulation of back-arc spreading, geodynamics of collision zones of lithospheric plates, geody- namics of rifts, stress state of the lithosphere, stress distribution and change in the lithosphere and asthenosphere during mantle upwelling and geological structures evo- lution. Modelling gives possibility to calculate P-T parameters distribution in the lay- ers of lithosphere and asthenosphere in the process of the evolution. Some geological effects can be explained by mantle dynamics. The existing of stretching zones in back arc basins can be explained by upwelling of mantle diapirs as a result of geothermal effect and raising of asthenosphere in the process of collision of deep mantle flows. In analitical decision it is possible to find critical parameters of the problem, connecting the form of diapir, its depth and velocity with structure of the Earth's surface. Defin- ing boundary conditions on the basement surface it is possible to make some conclu- sions about deep mooving in asthenosphere. Mantle upwelling can be evaluated by geothermal-gravity data. The results of modelling are investigated on the examples of the Pre-Caspian Depression, Russian Platform, Baikal rift, sedimentary basins of Brazil, Pacific and Alpine belts geological structures and give good agreement with geological-geophysical data.

Svalova, V. B.

35

A satellite remote sensing technique for geological structure horizon mapping  

Energy Technology Data Exchange (ETDEWEB)

A Satellite Remote Sensing Technique is demonstrated for generating near surface geological structure data. This technique enables the screening of large areas and targeting of seismic acquisition during hydrocarbon exploration. This is of particular advantage in terrains where surveying is logistically difficult. Landsat Thematic Mapper (TM) data and a high resolution Digital Elevation Model (DEM), are used to identify and map outcropping horizons. These are used to reconstruct the near surface structure. The technique is applied in Central Yemen which is characterised by a {open_quote}layer-cake{close_quote} geological and low dipping terrain. The results are validated using 2D seismic data. The near surface map images faults and structure not apparent in the raw data. Comparison with the structure map generated from a 2D seismic data indicates very good structural and fault correlation. The near surface map successfully highlights areas of potential closure at reservoir depths.

Fraser, A.; Huggins, P.; Rees, J. [Gas Research Centre, Loughborough (United Kingdom)] [and others

1996-08-01

36

Geometric modeling and optimization of three-dimensional geologic structures  

Energy Technology Data Exchange (ETDEWEB)

The optimization of criteria related to geophysical data (e.g. seismic waves travel times) is the most used method for the determination of geological structures in petroleum exploration. In this thesis, we propose to define geological criteria whose optimization, simultaneously with geophysical ones, will permit to obtain a better constrained underground model. To do that, we use the geometrical concept of foliations to describe sedimentary structures and we represent such a foliation by one of its parametric representations. The study of the unit normal vector field and its directional derivative leads us to define geometrical data (normal vector, convergence vector, total curvature, mean curvature, axial curvature) traducing structure`s geological properties (dip, parallelism, developability, smoothness of interfaces, folds axis directions). The extrapolation problem consists in the optimization of these criteria under equality constraints. This problem, considers a single foliation and only the geological criteria. This approach permits to show the effects of the different data. The canonical indetermination, due to the multiplicity of parameterization describing the same geometrical object, is locally solved by a theorem we demonstrate. This leads us to implement a general method which allows to obtain interesting numerical results. Finally, we study the C{sub 2}-parametrization space and we deduce some partial conclusions about the existence and the unicity of a continuous solution to the extrapolation problem. 39 refs., 49 figs, 4 appendices.

Rakotoarisoa, H.

1992-11-01

37

Expandable tubulars for use in geologic structures  

Energy Technology Data Exchange (ETDEWEB)

An expandable tubular includes a plurality of leaves formed from sheet material that have curved surfaces. The leaves extend around a portion or fully around the diameter of the tubular structure. Some of the adjacent leaves of the tubular are coupled together. The tubular is compressed to a smaller diameter so that it can be inserted through previously deployed tubular assemblies. Once the tubular is properly positioned, it is deployed and coupled or not coupled to a previously deployed tubular assembly. The tubular is useful for all types of wells and boreholes.

Spray, Jeffery A.; Svedeman, Steven; Walter, David; Mckeighan, Peter; Siebanaler, Shane; Dewhurst, Peter; Hobson, Steven; Foss, Doug; Wirz, Holger; Sharpe, Aaron; Apostal, Michael

2014-08-12

38

Evaluation of ERTS-1 data applications to geologic mapping, structural analysis and mineral resource inventory of South America with special emphasis on the Andes Mountain region. [Bolivia, Chile, and Peru  

Science.gov (United States)

The author has identified the following significant results. The La Paz Mosaic and its attendant overlays serve as a model for geologic studies elsewhere in the world. The P.I. and two geologists are mapping the conterminous states at scales of 1:5000,000 and 1:1,000,000. The 1:5 million band 5 mosaic was completed in two days of analysis. The 1:1 million band sheets are being completed at the rate of one per day. Comparison of the preliminary results of the three investigators shows a high correlation of linear and curvilinear features. Comparison with magnetic and gravity data indicates that many features being mapped are deep seated structures that have been active through long periods of geologic time, perhaps dating back to the Precambrian period. A detailed analysis of the El Salvador mining district has been completed. The interpretation is extremely detailed showing a complex pattern of linear features and bedrock outcrop patterns. This is the first product from ERTS-1 to be provided by Chile and shows a high degree of expertise in image interpretation. The Chileans are enthusiastic about their results and are anxious to map the entire country using ERTS.

Carter, W. D. (principal investigator)

1974-01-01

39

Effects of Rock Type and Geologic Process on the Structure and Evolution of Nano, Meso and Micro-Scale Porosity: A (U)SANS, SEM/BSE Analysis  

Science.gov (United States)

The microstructure and evolution of porosity in time and space play a critical role in many geologic processes, including the migration and retention of water, gas and hydrocarbons, the evolution of hydrothermal systems, weathering, diagenesis and metamorphism, as well as technological processes such as CO2 sequestration, shale gas and secondary oil recovery. The size, distribution and connectivity of these confined geometries collectively dictate how fluids migrate into and through these micro- and nanoenvironments, wet and react with mineral surfaces. (Ultra)small-angle neutron scattering and autocorrelations derived from SEM/BSE imaging provide a method of quantifying pore structures in a statistically significant manner from the nanometer to the centimeter scale. Data from this approach suggests that there are significant primary and evolutionary differences between the multiscale pore structures of carbonate and clastic rocks. Our work on the St. Peter sandstone shows total porosity correlates with changes in pores structure including pore size ratios, surface fractal dimensions, and lacunarity. There is no evidence of mass-fractal scattering and while previous scattering data from sandstones suggest scattering is dominated by surface fractal behavior over many orders of magnitude, our data show both fractal and pseudo-fractals. Larger pores fill at a faster rate than small pores as overgrowths form, leading to an increase in the small/large pore ratio. Overall, therefore, the relative importance of fluid reactions in confined geometries is likely to increase with increased silcrete formation. The changes observed with overgrowth formation in sandstones contrast with available data for metamorphism of chemical sediments (limestones) in both the Marble Canyon contact aureole, TX (Anovitz et al., 2009), and the Hatrurim Fm. (the Mottled Zone), Israel. The unmetamorphosed limestones both show distinct multifractal scattering patterns at larger scales, and true surface fractals at smaller scales. Total porosity increases with metamorphism, as does the surface area to volume ratio. The mass fractal dimension increases with metamorphic grade. In the Hatrurim the surface fractal dimension also increase suggesting that increases in pore mass density and formation of less branching pore networks are accompanied by a roughening of pore/grain interfaces. Ds changes are more complex at Marble Canyon, possibly due to hydrothermal processes. Pore evolution during combustion metamorphism is also characterized by reduced contributions from small-scale pores to the cumulative porosity in the high-grade rocks. The evolution of pore/grain microstructures may be correlated to the growth (nucleation) of high-temperature phases that preferentially close small pores, producing a rougher morphology with increasing temperature. The transition to a rough morphology may be a consequence of pore/grain surface free energies that are smaller than those that arise from heterogeneous phase contacts. Large-scale pores may also develop at the expense of small-scale pores. [1] Anovitz et al. (2009) Geochimica et Cosmochimica Acta 73, 7303-7324. Research sponsored by the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences, U.S. Department of Energy.

Anovitz, L.; Wang, H.; Cole, D. R.; Rother, G.

2012-12-01

40

The application of Synchrotron radiation based microtomography in (structural) geology  

Science.gov (United States)

Synchrotron radiation based tomography (SRT) is a well established, yet still improving technique to image the internal microstructure of a wide range of materials in three dimensions. It benefits from the very high photon flux provided by synchrotron sources, which is collimated in a very small, coherent photon beam covering a continuous energy spectrum of up to 100 keV. Imaging techniques such as absorption contrast, absorption edge and phase contrast tomography as well as automated sample loading render the method very flexible for addressing a large number of scientific questions concerning rock microstructure. With different end stations for micro- and nanotomography achieving spatial resolutions of several hundred down to a few tens of nanometers, SRT provides three-dimensional microstructural data that bridge a critical gap towards the nanoscale. In combination with high-speed cameras even dense rock samples can be imaged in fractions of seconds, leading the way to time-resolved studies in 3D. Beyond the stunning three-dimensional insights that SRT data provide into rock microstructure, such data allow a quantitative and time-dependent characterisation of rock properties. On the way to such a characterisation, the quantitative analyses of three- and four-dimensional SRT data may pose a significant challenge for the user. The analyses are demanding in terms of the necessary hardware and software, and the procedure involves a number of possible technical pitfalls and analytical error sources. However, mastering these challenges means opening a new approach to experimental as well as computational rock mechanics and microstructural geology. Increasingly, these approaches are included in the multi-scale characterisation of rocks and their mechanical properties. This presentation aims at reviewing the potential of Synchrotron radiation based microtomography for research applications in structural geology and experimental rock mechanics. Besides outlining the technical capabilities of the latest generation of microtomography beam lines at the Advanced Photon Source (USA), we will present our workflow for the analysis of large time-resolved tomographic datasets. We will conclude with an outlook on a next generation of in-situ studies on fluid-rock interaction and rock deformation. Acknowledgment: Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.

Fusseis, F.; Xiao, X.; Schrank, C.; Liu, J.; De Carlo, F.

2012-04-01

 
 
 
 
41

2005 dossier: granite. Tome: safety analysis of the geologic disposal  

International Nuclear Information System (INIS)

This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the safety aspects of the geologic disposal of high-level and long-lived (HLLL) radioactive wastes in granite formations. Content: 1 - safety approach: context and general goal, references, design approach by safety functions, safety approach during the construction-exploitation-observation-closure phase, safety analysis during the post-closure phase; 2 - general description: HLLL wastes, granitic environment, general structure of the architecture of a disposal facility; 3 - safety functions and disposal design: general context, safety functions of the long-term disposal, design dispositions retained to answer the functions; 4 - operational safety: people's protection, radiological risks during exploitation, risk analysis in accident situation; 5 - qualitative safety analysis: methodology, main results of the analysis of the features, events and processes (FEP) database; 6 - disposal efficiency evaluation during post-closure phase: calculation models, calculation tools used for the modeling of radionuclides transport, calculation results and main lessons. (J.S.)

42

Geologic Framework Model Analysis Model Report  

International Nuclear Information System (INIS)

ed in the appropriate text sections that follow. The GFM is one component of the Integrated Site Model (ISM) (Figure l), which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1) Geologic Framework Model (GFM); (2) Rock Properties Model (RPM); and (3) Mineralogic Model (MM). The ISM merges the detailed project stratigraphy into model stratigraphic units that are most useful for the primary downstream models and the repository design. These downstream models include the hydrologic flow models and the radionuclide transport models. All the models and the repository design, in turn, will be incorporated into the Total System Performance Assessment (TSPA) of the potential radioactive waste repository block and vicinity to determine the suitability of Yucca Mountain as a host for the repository. The interrelationship of the three components of the ISM and their interface with downstream uses are illustrated in Figure 2

43

Methods to enhance geological structures in remotely sensed images based on the spatial difference of spectrum and their applications  

Science.gov (United States)

Geological structures used to be faint and blur in remotely sensed image as they are usually buried or hidden under the ground. In spite of that, the information of them can be found out in single band or multi-bands of the multi-spectrum data. Geological structures can be considered as image anomalies upon complex background. It is an important approach for geological structure enhancement to enhance the difference between the anomaly and its background in single band or multi-bands. Characteristics of spatial spectral distribution is thus special significant for image processing. Along this way, we improved on two methods, mean-residue (MR) and selective principal component analysis (SPCA), with emphasis on spatial spectral analysis, to enhance geological structures. Applications of the methods to actual TM data have arrived at good results. The keys of the two methods are respectively the determination of filter kernel and the selection of band pair.

Liu, Jiping; Zhang, Qiuwen; Zuo, Zhengrong; Yuan, Yanbing

2001-09-01

44

Determination of subsurface geological structure with borehole gravimetry  

International Nuclear Information System (INIS)

Conventional gamma-gamma and gravimetric density measurements are routinely gathered for most holes used for underground nuclear tests. The logs serve to determine the subsurface structural geology near the borehole. The gamma-gamma density log measures density of the rock within about 15 cm of the borehole wall. The difference in gravity measured at two depths in a borehole can be interpreted in terms of the density of an infinite, homogeneous, horizontal bed between those depths. When the gravimetric density matches the gamma-gamma density over a given interval it is assumed that the bed actualy exists, and that rocks far from the hole must be the same as those encountered adjacent to the borehole. Conversely, when the gravimetric density differs from the gamma-gamma density it is apparent that the gravimeter is being influenced by a rock mass of different density than that at the hole wall. This mismatch can be a powerful tool to deduce the local structural geology. The geology deduced from gravity mesurements in emplacement hole, U4al, and the associated exploratory hole, UE4al, is an excellent example of the power of the method

45

Information Theory and the Analysis of Uncertainties in a Spatial Geological Context  

Science.gov (United States)

The interpretation of uncertainties in a spatial context is of fundamental importance for the generation of structural geological models; this applies to models for mineral exploration, to scientific structural geological studies and fundamental geological evaluations. With our work, we are addressing uncertainties in this spatial geological context. Encouraged by the interdisciplinary and interactive aspect of the session, we would like to present our method to other branches of geosciences. Structural geological models, here understood as structural representations of the dominant geological units in the subsurface, always contain uncertainties. The analysis of these uncertainties is intricate as these models are usually constructed on the basis of greatly varying data quality and spatial distribution. An additional complication is that, in most cases, the general distribution of uncertainties in space is of interest, and not a single outcome as, for example, the flow at a well. In the context of structural geological uncertainties, we therefore face two problems: (i) how can we estimate uncertainties in a complex 3-D geological model, and (ii) what is a meaningful measure to visualise and analyse these uncertainties quantitatively? In recent years, several approaches have been developed to solve the first problem. We show here an approach based on implicit stochastic geological modelling techniques, capable of handling complex geological settings. To address the second problem, we apply measures from information theory. We consider each subspace in a discretised model domain as a random variable. Based on the probability functions estimated from a suite of generated models, we evaluate the information entropy at each location in the subsurface as a measure of uncertainty. We subsequently estimate multivariate conditional entropy and mutual information between a set of locations and other regions in space, to determine spatial uncertainty correlations, and the potential reduction of uncertainty with additional information. We apply these information theoretic measures to a case study where uncertainties exist about the structure, and shape, of a bounded geological unit at depth. The results yield some, at first, surprising, but very reasonable results for the interpretation of uncertainties. The case study highlights the fact that information theoretic measures provide very intuitive measures of uncertainty, but, due to the relation of the measure to Bayesian theory, also combine them with a powerful quantitative meaning.

Wellmann, Florian; Jessell, Mark

2014-05-01

46

Seismicity and Geologic Structures Indubitable in Wadi Hagul, North Eastern Desert, Egypt  

Directory of Open Access Journals (Sweden)

Full Text Available Paleo and recent earthquakes have been recorded in Wadi Hagul area and its environs, which have left behind geologic structures of deformation preserved in exposed sedimentary rocks. To evaluate such deformation and surface break, different techniques and data types are used compromising image processing techniques, Geographic Information Systems (GIS, seismicity data, as well as, field investigation. The field investigation clarified that the study area is enriched with soft-sediment deformation structures encompassing two types of geologic structures; brittle and viscoplastic structures. The analysis of the various types of data elucidate that, the earthquakes of Wadi Hagul are frequently distributed at an average depth ranging from (1 to 35 km within the top of the Earth’s crust which are mainly controlled by existing Hagul fault zone. The study gives new insight for a better understanding of the seismic activity in the study area which helps in the seismic hazard assessment

Tarek A. Seleem

2011-02-01

47

Spatial Abilities of High-School Students in the Perception of Geologic Structures.  

Science.gov (United States)

Characterizes specific spatial abilities required in geology studies through the examination of the performance of high school students in solving structural geology problems on the geologic spatial ability test (GeoSAT). Concludes that visual penetration ability and the ability to perceive the spatial configuration of the structure are…

Kali, Yael; Orion, Nir

1996-01-01

48

Precomputing upscaled hydraulic conductivity for complex geological structures  

Science.gov (United States)

3D geological models are built to capture the geological heterogeneity at a fine scale. However groundwater modellers are often interested in the hydraulic conductivity (K) values at a much coarser scale to reduce the numerical burden. Upscaling is used to assign conductivity to large volumes, which necessarily causes a loss of information. Recent literature has shown that the connectivity in the channelized structures is an important feature that needs to be taken into account for accurate upscaling. In this work we study the effect of channel parameters, e.g. width, sinuosity, connectivity etc. on the upscaled values of the hydraulic conductivity and the associated uncertainty. We devise a methodology that derives correspondences between a lithological description and the equivalent hydraulic conductivity at a larger scale. The method uses multiple-point geostatistics simulations (MPS) and parameterizes the 3D structures by introducing continuous rotation and affinity parameters. Additional statistical characterization is obtained by transition probabilities and connectivity measures. Equivalent hydraulic conductivity is then estimated by solving a flow problem for the entire heterogeneous domain by applying steady state flow in horizontal and vertical directions. This is systematically performed for many random realisations of the small scale structures to enable a probability distribution for the equivalent upscaled hydraulic conductivity. This process allows deriving systematic relationships between a given depositional environment and precomputed equivalent parameters. A modeller can then exploit the prior knowledge of the depositional environment and expected geological heterogeneity to bypass the step of generating small-scale models, and directly work with upscaled values.

Mariethoz, G.; Jha, S. K.; George, M.; Maheswarajah, S.; John, V.; De Re, D.; Smith, M.

2013-12-01

49

Applicability of neutron activation analysis to geological samples  

Energy Technology Data Exchange (ETDEWEB)

The applicability of neutron activation analysis (NAA) to geological samples in space is discussed by referring to future space mission programs, by which the extraterrestrial samples are to be delivered to the earth for scientific inspections. It is concluded that both destructive and non-destructive NAA are highly effective in analyzing these samples. (author)

Ebihara, Mitsuru [Tokyo Metropolitan Univ., Graduate School of Science, Tokyo (Japan)

2003-03-01

50

Neutron activation analysis of osmium in geological samples  

International Nuclear Information System (INIS)

A neutron activation analysis procedure was developed for the determination of osmium in geological materials. The method consists in the measurement of the 129.4 keV ?-rays of 191Os after radiochemical separation of osmium. The sample decomposition, the chemical separation process and the optimal measuring conditions are described and discussed. (author)

51

Applicability of neutron activation analysis to geological samples  

International Nuclear Information System (INIS)

The applicability of neutron activation analysis (NAA) to geological samples in space is discussed by referring to future space mission programs, by which the extraterrestrial samples are to be delivered to the earth for scientific inspections. It is concluded that both destructive and non-destructive NAA are highly effective in analyzing these samples. (author)

52

Geological Geophysical and structural studies in Mina Ratones (Pluton de Albala)  

International Nuclear Information System (INIS)

Mina Ratones environmental restoration project included petrological, structural,geophysical, hydrogeological and hydrogeochemical studies. The main objective of the geologic-structural and geophysical studies was the Albala granite structural characterization around the Mina Ratones uranium mine. The location of facies, fault zones (faults and dykes) as well as the distribution of some physical properties inside the rock massif was obtained for a granitic black of 900, 500, and 500 m. The geologic-structural and geophysical techniques applied to Mina Ratones provided a multidisciplinary approach for high resolution characterization of rock massif, and the structures potentially containing fluids,able to be applied to the hydrogeological modelling to a particular area. Geological studies included a detailed structural mapping of the area surrounding the mine (1:5,000 scale), the geometric, kinematics, and dynamics analysis of fractures of all scales, the petrology and geochemistry of fault rocks and altered areas surrounding fractures, and the microstructural studies of samples from surface and core lags. The construction of geostatistical models in two and three dimensions had helped to characterize the Mina Ratones rock massif showing the spatial distribution of fault zones, fracture intensity, granite composition heterogeneities, fluid-rock interaction zones, and physical properties. (Author)

53

A satellite remote-sensing technique for geological horizon structure mapping  

Energy Technology Data Exchange (ETDEWEB)

A Satellite Remote Sensing technique is demonstrated which provides accurate and cost effective near-surface geological structure data. In the exploration phase the technique enables the rapid and inexpensive screening of open licences and the targeting of seismic acquisition, particularly important in terrains of difficult data acquisition. This paper describes the satellite data used, the technique of horizon surface data extraction and the analysis of a case study from Yemen. Landsat Thematic Mapper (TM) data and a high resolution digital elevation model (DEM), generated from stereo SPOT panchromatic images, are used in conjunction to identify a number of outcropping horizons and map their spatial position and height. Geological contacts are identified and digitised from the Landsat TM data and the elevations of these points taken from the digital elevation data. The extracted x,y,z co-ordinates are then gridded to construct a horizon structure map. The technique is applied to an area of central Yemen which is characterised by a near-surface {open_quote}layer cake{close_quote} geological structure in an extremely low dipping terrain (Less than 1{degrees}). The remote sensing interpretation is validated by comparison with 2D seismic across the area. Regional flexural structures with bed dips of as little as 0.25{degrees} can be mapped. Trend analysis and residual calculations on the horizon structure map show the techniques ability to identify and quantify horizon deformation related to faulting. Surface geological structure was successfully interpolated into the subsurface indicating potential fault closure at reservoir target depths.

Fraser, A.J.; Huggins, P.; Cleverley, P.H.; Rees, J.L.

1995-12-31

54

Computer methods for geological analysis of radiometric data  

International Nuclear Information System (INIS)

Whether an explorationist equates anomalies with potential uranium ore deposits or analyses radiometric data in terms of their relationships with other geochemical, geophysical, and geological data, the anomaly or anomalous zone is the most common starting point for subsequent study or field work. In its preliminary stages, the definition of meaningful anomalies from raw data is a statistical problem requiring the use of a computer. Because radiometric data, when properly collected and reduced, are truly geochemical, they can be expected to relate in part to changes in surface or near-surface geology. Data variations caused strictly by differences in gross chemistry of the lithologies sampled constitute a noise factor which must be removed for proper analysis. Texas Instruments Incorporated has developed an automated method of measuring the statistical significance of data by incorporating geological information in the process. This method of computerized geological analysis of radiometric data (CGARD) is similar to a basic method of the exploration geochemist and has been proved successful in its application to airborne radiometric data collected on four continents by Texas Instruments Incorporated. This beginning and its natural follow-on methods of automated or interpretive analysis are based simply on the perception of radiometric data as sets of statistically distributed data in both the frequency and spatial domains. (author)thor)

55

The EVEREST project: sensitivity analysis of geological disposal systems  

International Nuclear Information System (INIS)

The main objective of the EVEREST project is the evaluation of the sensitivity of the radiological consequences associated with the geological disposal of radioactive waste to the different elements in the performance assessment. Three types of geological host formations are considered: clay, granite and salt. The sensitivity studies that have been carried out can be partitioned into three categories according to the type of uncertainty taken into account: uncertainty in the model parameters, uncertainty in the conceptual models and uncertainty in the considered scenarios. Deterministic as well as stochastic calculational approaches have been applied for the sensitivity analyses. For the analysis of the sensitivity to parameter values, the reference technique, which has been applied in many evaluations, is stochastic and consists of a Monte Carlo simulation followed by a linear regression. For the analysis of conceptual model uncertainty, deterministic and stochastic approaches have been used. For the analysis of uncertainty in the considered scenarios, mainly deterministic approaches have been applied

56

SITE-94. Development of a geological and a structural model of Aespoe, southeastern Sweden  

International Nuclear Information System (INIS)

The objective of the present study is to construct three-dimensional geological and structural models to be used within the SKI SITE-94 project as a base for modelling hydrogeological, hydrochemical, and rock mechanical bedrock conditions, mass transport and layout of a hypothetical repository. The basic input data in the SITE-94 geological and structural models are restricted to geological and structural readings and geophysical measurements made prior to building the Hard Rock Laboratory. 114 refs, 82 figs, 28 tabs

57

Unraveling African plate structure from elevation, geoid and geology data  

Science.gov (United States)

The aim of our project is to simulate the long-wavelength, flexural isostatic response of the African plate to sediment transfers due to Meso-Cenozoic erosion - deposition processes in order to extract the residual topography driven by mantle dynamics. Our work will be based on the reconstruction and subtraction of two continental-scale erosional-depositional surfaces of Eocene and Late Cretaceous ages and their offshore extensions. The first step of our project consists in computing crustal and lithospheric maps of the African plate considering its various crustal geological components (cratons, mobile belts, basins, rifts and passive margins of various ages and strengths). In order to consider these heterogeneities, we compute a 2D distribution of crustal densities and thermal parameters from geological data and use it as an input of our modeling. We combine elevation and geoid anomaly data using a thermal analysis, following the method of Fullea et al. (2007) in order to map crustal and lithospheric thicknesses. In this approach, we assume local isostasy and consider a four-layer model made of crust and lithospheric mantle plus seawater and asthenosphere. In addition, we compare our results with crustal thickness datasets compiled from bibliography, existing global models such as CRUST 1.0, and tomographic lithospheric models. The obtained crustal thicknesses range from 30 to 45km, with the thickest crust confined to the northern part of the West African Craton, the Kaapvaal craton, and the Congo cuvette. The crust in the East African Rift appears unrealistically thick (40-45 km) as it is not isotatically compensated, highlighting the dynamic effect of the African superswell. The thinnest crust (30-35km) follows a central East-West trend coinciding with Cretaceous rifts and the Cameroon volcanic line. Pan-African mobile belts yield intermediate values of ca. 35-40 km. The lithosphere reaches 250 km beneath cratons, but remains globally thin (ca. 150-180 km) compared to tomographic models and considering the age of most geological provinces. As for the crust, the thinnest lithosphere is located in areas of Cretaceous-Jurassic rifting. References: Fullea J., Fernàndez M., Zeyen H., Vergés J., 2007. A rapid method to map the crustal and lithospheric thickness using elevation, geoid anomaly and thermal analysis. Application to the Gibraltar Arc System, Atlas Mountains and adjacent zones. Tectonophysics 430, 97-117.

Chardon, Dominique; Bajolet, Flora; Robert, Alexandra; Rouby, Delphine

2014-05-01

58

Characteristics of geological structure with the Lira explosions and possible ways of radionuclide migration  

International Nuclear Information System (INIS)

Peaceful nuclear explosions were detonated on the northern side of Karachaganak deposit to create cavities for storing gas condensate. Despite the detailed study of the salt dome by means of drilling, a number of questions were not answered, regarding internal structure of space above the dome, and salt tectonics. These questions are important for prognosis of radionuclide contamination of territory. By means of acquisitions, and analysis of geologic information, and reconstruction of structures, one can forecast four stratigraphic levels for possible migration of radionuclides. It is recommended to use the acquired data during the experimental researches of 'Lira' explosions. (author)

59

Combined NLCG/SBI magnetotelluric data inversion for recognition of complex geological structures  

International Nuclear Information System (INIS)

Complete text of publication follows. Geological interpretation of magnetotelluric data is a subject of some misunderstandings. Simplified geometrically and well contrasted in resistivity models do not response for real geological environment. The aim of outstripping magnetotelluric works widely made in Polish Outer Carpathians, is general structural and lithological recognising of geological environment and distinguishing of areas where oil prospection will be projected. The geological medium is formed by sedimentary formations, strongly deformed and containing relatively thin layers with essentially differentiated parameters, overlying rather flat, high resistivity basement. Application of simplified strongly contrasted interpretation model with fluently changing parameters gives frequently results not corresponding with geological reality. Presented analysis is based on surveys located in marginal zone of Carpathianst in the area relatively well recognised, where interpreted structural and lithologic model rather well reflects real geological medium. Then, it was used as reference model for obtained results of MT data inversion. Magnetotelluric continuous profiling located along reflection seismic profile, between two deep boreholes was made. Set of results of computations allows to evaluate of effectiveness of used procedures and suggest optimum way of dealing. First stage of data interpretation was based on 1D and EMAP inversion. The section was then applied as starting model for 2D NLCG inversion. Results of this method give rather generalized resistivity distribution well reflecting structure of flysch cover but not adequate for the basement. This models was applied as starting models for SBI inversion constrained by borehole data. Results of SBI procedure well reflects relatively flat complexes of the basement, but are rather unrealistic for folded flysch cover. The another NLCG inversion was computed with stabilised model of basement obtained from SBI inversion. Obtained resistivity cross section was relatively concordant to reference model. This paper is a result of the statutory research of the Department of General Geology, Environment Protection and Geotourism, project No 11.11.140.447. Results of project supported by grant from the Ministry of Scientific Research and Information Technology under contract no 5T12B 041 25 were also used.

60

Geology of the Upheaval Dome impact structure, southeast Utah  

Science.gov (United States)

Two vastly different phenomena, impact and salt diapirism, have been proposed for the origin of Upheaval Dome, a spectacular scenic feature in southeast Utah. Detailed geologic mapping and seismic refraction data indicate that the dome originated by collapse of a transient cavity formed by impact. Evidence is as follows: (1) sedimentary strata in the center of the structure are pervasively imbricated by top-toward-the-center thrust faulting and are complexly folded as well; (2) top-toward-the-center normal faults are found at the perimeter of the structure; (3) clastic dikes are widespread; (4) the top of the underlying salt horizon is at least 500 m below the surface at the center of the dome, and there are no exposures of salt or associated rocks of the Paradox Formation in the dome to support the possibility that a salt diapir has ascended through it; and (5) planar microstructures in quartz grains, fantailed fracture surfaces (shatter surfaces), and rare shatter cones are present near the center of the structure. We show that the dome formed mainly by centerward motion of rock units along listric faults. Outcrop-scale folding and upturning of beds, especially common in the center, are largely a consequence of this motion. We have also detected some centerward motion of fault-bounded wedges resulting from displacements on subhorizontal faults that conjoin and die out within horizontal bedding near the perimeter of the structure. The observed deformation corresponds to the central uplift and the encircling ring structural depression seen in complex impact craters. Copyright 1999 by the American Geophysical Union.

Kriens, B. J.; Shoemaker, E. M.; Herkenhoff, K. E.

1999-01-01

 
 
 
 
61

Typhoon-triggered landslides and regional geological structure: case from Typhoon Morakot in Taiwan  

Science.gov (United States)

Typhoon Morakot invading Taiwan on August 8th, 2009 caused numerous major disasters throughout the island. Exceeding rainfall threshold in many sides in mountainous areas triggered slope failure leading to widespread damage and loss of life. Hsiaolin village located at the foothills of Shiendu Shan on the third day typhoon existence was entirely buried by massive landslide. This tragic event left absolute necessity of studying such incidents due to understanding those phenomena. A detail field investigation focused on structural measurement, around whole the Hsiaolin landslide as well as its surrounding area, has been carried out in this study. In order to realize the landslide mechanism of regional settings, we focused on the affect of geological structures and stress analysis around the study area. Wedge failure had been observed at numerous outcrops, which produced by bedding and fault systems' inter-cutting at the dip-slope area of the mountains. Therefore, in some areas landslide could have happen even in dry season with relative stable condition. Mountains of SW Taiwan is very susceptible and landslides are easily happened even by a minor factor. After a detailed investigation we came to a conclusion that structure geological setting played a major role as a direct factor for creating the regional landslide. By considering the geometric correlation between geological structure, strata attitude and topography, a objective hazard map can be provided. In this map, study area can be classified into different slope stability level, which implied different probability of landslide. Our study proved the importance of structural measurement in landslide study. The results derived from the structural analysis can also be applied for improving advanced estimations of other related studies.

Huang, C.-C.; Chang, C.-P.; Giletycz, S. J.

2012-04-01

62

Activation analysis of strontium and barium in geological samples  

International Nuclear Information System (INIS)

Radiochemical ion-exchange procedure has been developed for the analysis of strontium and barium in geological samples based on the use of short lived isotopes sup(87m)Sr and 139Ba. Accuracy and precision were evaluated by analysing geological standard rocks and the results obtained are presented and compared. Samples and standards were irradiated for 4 hours at a flux of 5x1011n cm-2s-1 and allowed to cool for 30 min before processing. The photopeak intensities of 388 keV sup(87m)Sr and 166 KeV 139Ba were calculated by the method of Covell. The precision of the method is of the order of 9% for strontium at 120 ppm level and 6.5% for barium at 1200 ppm level. The method is fairly rapid takes 4 hours for the complete processing of 4 samples and 2 standards. (T.I.)

63

Multipass SAR interferometry. A tool for geologic analysis  

International Nuclear Information System (INIS)

This paper investigates how the information content of repeat pass satellite SAR interferometric (INSAR) data can be used to provide the geologist with a tool which can improve his ability and efficacy in the geologic analysis of SAR imagery. INSAR processing produces interferometric fringes, coherence and amplitude images. To produce an interferometric DEM phase unwrapping is a critical step. For phase unwrapping, it is proposed the WLMS (Weighted Least Mean Square) estimation of the phase, which is a generalization of the least-mean square method. The crucial step in WLMS approach is the weighting procedure. It is proposed a weighting algorithm based on the fusion of a priori information extracted from different interferometric products. These different information channels-DEM, amplitude and coherence-can be effectively fused to convey information to the geologic interpreter using 3D stereoscopic visualization; SAR stereo pairs were artificially generated using the interferometric DEM and the intensity image or the coherence image of the area overlaid. In order to ascertain the performance of the procedure a number of tests were carried out over various sites in Matese (Southern Italy), which has a fairly demanding topography, using ERS SAR tandem data. The results demonstrate that WLMS unwrapping method is sufficiently robust in capturing the morphology of the area and that stereoscopic visualization greatly facilities geologic interpretation and the observation ologic interpretation and the observation of detailed features of the terrain

64

Geological-structural interpretation using products of remote sensing in the region of Carrancas, Minas Gerais, Brazil  

Science.gov (United States)

The efficiency of some criteria developed for the utilization of small scale and low resolution remote sensing products to map geological and structural features was demonstrated. Those criteria were adapted from the Logical Method of Photointerpretation which consists of textural qualitative analysis of landforms and drainage net patterns. LANDSAT images of channel 5 and 7, 4 LANDSAT-RBV scenes, and 1 radar mosiac were utilized. The region of study is characterized by supracrustal metassediments (quartzites and micaschist) folded according to a "zig-zag" pattern and gnaissic basement. Lithological-structural definition was considered outstanding when compared to data acquired during field work, bibliographic data and geologic maps acquired in larger scales.

Parada, N. D. J. (principal investigator); Dossantos, A. R.; Dosanjos, C. E.; Barbosa, M. P.; Veneziani, P.

1982-01-01

65

A mathematical formulation for large strain analysis of geologic continua  

Energy Technology Data Exchange (ETDEWEB)

A solution method is presented for finite-deformation analysis of geologic materials. The principle of virtual work is used to state the equations of equilibrium in a weak form. These equations are linearized about the last-established equilibrium configuration. A material constitutive relationship between the Green-Naghdi stress rate and the rate-of-deformation tensor is used to obtain the current stresses. The finite-element governing equations are expressed in a form suitable for an iterative solution strategy. The obtained gradient matrix contains the effects of both material and geometric nonlinearities. The primary application area of this formulation is the analysis of long-term deformation response of the region adjoining the mining shafts and the waste emplacement rooms within a nuclear waste repository. In this region, the strains are expected to be large, and the infinitesimal strain analysis would introduce inaccuracies in the solution. 19 refs., 6 figs.

Chaudhary, A.B.; Vakili, J.E.; Hume, H.R.

1987-12-01

66

Diversion path analysis for the Swedish geological repository  

Energy Technology Data Exchange (ETDEWEB)

The Swedish strategy to handle the spent fuel from the nuclear power plants is direct disposal in a geological repository. The safeguards regime covering all nuclear material in the state will be expanded to cover the new repository, which will require a novel safeguards approach due mainly to the inaccessibility of the fuel after disposal. The safeguards approach must be able to provide a high level of assurance that the fuel in the repository not diverted, but must also be resource efficient. An attractive approach with regards to use of resources is to monitor only the access points to the repository, i.e. the openings. The implementation of such an approach can only be allowed if it is shown to be sufficiently secure. With the purpose of determining the applicability of this 'black box' approach, a diversion path analysis for the Swedish geological repository has been carried out. The result from the analysis shows that all credible diversion paths could be covered by the black-box safeguards approach provided that the identified boundary conditions can be met

Fritzell, Anni (Dept. of Physics and Astronomy, Uppsala Univ., Uppsala (Sweden)); Meer, Klaas Van Der (Belgian Nuclear Research Center SCK.CEN (BG))

2008-02-15

67

Overview of continuum and particle dynamics methods for mechanical modeling of contractional geologic structures  

Science.gov (United States)

Mechanically-based numerical modeling is a powerful tool for investigating fundamental processes associated with the formation and evolution of both large and small-scale geologic structures. Such methods are complementary with traditional geometrically-based cross-section analysis tools, as they enable mechanical validation of geometric interpretations. A variety of numerical methods are now widely used, and readily accessible to both expert and novice. We provide an overview of the two main classes of methods used for geologic studies: continuum methods (finite element, finite difference, boundary element), which divide the model into elements to calculate a system of equations to solve for both stress and strain behavior; and particle dynamics methods, which rely on the interactions between discrete particles to define the aggregate behavior of the system. The complex constitutive behaviors, large displacements, and prevalence of discontinuities in geologic systems, pose unique challenges for the modeler. The two classes of methods address these issues differently; e.g., continuum methods allow the user to input prescribed constitutive laws for the modeled materials, whereas the constitutive behavior 'emerges' from particle dynamics methods. Sample rheologies, case studies and comparative models are presented to demonstrate the methodologies and opportunities for future modelers.

Gray, Gary G.; Morgan, Julia K.; Sanz, Pablo F.

2014-02-01

68

Structural Geology and Microstructures of Wrangel Island, Arctic Russia  

Science.gov (United States)

Wrangel Island is a unique exposure of Neoproterozoic basement and upper Paleozoic and Mesozoic cover. Its geology is critical for testing the continuity of stratigraphic units and structures across the Chukchi Sea from Alaska to Russia, for constraining paleogeography and plate reconstructions of the Arctic and for evaluating the hydrocarbon potential of this offshore region. The Paleozoic stratigraphy of Wrangel correlates to the offshore Hannah Trough, Alaska, but its thick section of Triassic turbidites has no counterpart in Alaska (Miller et al., 2010, AAPG; Sherwood et al., 2002, GSA Spec. Paper 360). Wrangel Island lies on a regional structural high along strike of the offshore Herald Arch and Chukchi Platform, Alaska. To the north, the deep North Chukchi Basin, bound by ~E-NE trending, north-dipping normal faults, is inferred to contain up to 12 km of Beaufortian and Brookian (Late Jurassic to Tertiary) sediments in addition to Paleozoic strata (Dinkelman et al., 2008). To the south, ~E-W trending faults bound the Longa Basin that separates Wrangel from Chukotka and lies along strike of the early Tertiary Hope Basin. Wrangel Island was interpreted to represent a north-vergent Mesozoic to Tertiary fold and thrust belt traced offshore by seismic reflection to the Herald Arch and then to the Lisburne Hills and the Brooks Range foreland fold and thrust belt, (e.g. Kos’ko et al., 1993). However, deformation of Wrangel Island rocks differs significantly from typical foreland fold-thrust structures. Both cover and basement rocks have strong penetrative metamorphic fabrics. Foliation strikes E-W and dips ~40° S, with a pronounced N-S trending elongation or stretching lineation. Aspect ratios of stretched pebbles are ~ 5:1:.2 to 10:1:.1. The foliation is axial planar to tight/isoclinal folds at all scales and these also involve the basement-sediment contact. 25 oriented thin-sections of feldspathic sandstones and grits were examined for sense of shear and the fabrics in quartz-rich domains studied by electron back-scatter diffraction (EBSD). These studies indicate that systematic sense of shear indicators/asymmetric fabrics (top to the N versus top to the S) are uncommon and if present, not pervasive or consistent. EBSD studies of quartz fabrics together with growth of metamorphic biotite at deepest structural levels suggest temperatures as high as 450°C for deformation, with subsequent cooling at shallower levels of the crust to preserve the observed quartz microstructures. Cooling of rocks through 100°C based on apatite fission track ages occurred by ~ 95 Ma, providing a minimum age for deformation. The penetrative fabrics and large strains are more similar to high strain fabrics developed during extension such as those developed along the south flank of the Brooks Range, on the Seward Peninsula, and mainland Chukotka. It is inferred that structures on Wrangel Island formed during an episode of high heat flow and N-S ductile stretching of the crust, an interpretation compatible with the age constraints on the fabrics and the structural position of Wrangel between two large normal-fault bound basins.

Miller, E. L.; Dumitru, T. A.; Seward, G.

2010-12-01

69

Geological structure of the Paradox Valley Region, Colorado, and relationship to seismicity induced by deep well injection  

Science.gov (United States)

Bureau of Reclamation (Reclamation) operates a deep injection well at Paradox Valley in western Colorado. Seismicity has been recorded since 1985, with more than 5900 likely induced earthquakes detected since injection operations began in 1991, making this project a unique and valuable case study in the long-term development of injection-induced seismicity. Likely induced earthquakes occur in a complex pattern with clusters separated by aseismic gaps of 2 km or more, and have been observed up to 16 km from the injection well. To evaluate how the subsurface geologic structure may control the occurrence of induced seismicity, we compare the earthquake locations to a set of geologic models that Reclamation commissioned prior to drilling the injection well. Our analysis indicates that many aspects of the observed seismicity pattern can be attributed to the complex geologic structure. The earthquake depths and locations are generally consistent with the structural trends of the primary injection target formation, within the uncertainty of the models, and some of the mapped basement faults appear to serve as boundaries in the earthquake locations, suggesting that they are barriers to flow. Additionally, the majority of events follow the predicted fluid flow pattern, which trends northwest-southeast and wraps around Paradox Valley. Some features of the seismicity pattern, such as the early onset of seismicity to the northwest of the injection well and the distinct clustering, are not explained by the current geologic models and may be related to unmapped geologic features or local variations in the stress field.

King, Vanessa M.; Block, Lisa V.; Yeck, William L.; Wood, Christopher K.; Derouin, Sarah A.

2014-06-01

70

Earthquakes and Geological Structures of the St. Lawrence Rift System  

Science.gov (United States)

The St. Lawrence Rift System (SLRS), which includes the Ottawa-Bonnechère and Saguenay grabens, is located well inside the North American plate. Most historic and the some 350 earthquakes recorded yearly occur in three main seismically active zones, namely Charlevoix (CSZ), Western Quebec (WQSZ), and Lower St. Lawrence (LSLSZ)). Outside these areas, most of the Canadian Shield and bordering regions have had a very low level of earthquake activity. In the SLRS, moderate to large earthquakes (Moment magnitude (M) 5.5 to M 7) are known to have occurred since 1663 causing landslides and damage mostly to unreinforced masonry elements of buildings located on ground capable of amplifying ground motions. Most earthquakes in these seismic zones share common characteristics such as mid- to upper crustal focal depths, no known surface ruptures and proximity to SLRS faults. Variations also exist such as vast seismically-active region (WQSZ and LSLSZ), presence of a large water body (CSZ and LSLSZ), and absence of SLRS faults near concentration of earthquakes (WQSZ). The CSZ is the best studied seismic zone and there, earthquakes occur in the Canadian Shield, mostly in a 30 X 85 km rectangle elongated along the trend of the St. Lawrence River with local variations in focal depth distribution. Faults related to the SLRS and to a meteor impact structure exist and earthquakes occur along the SLRS faults as well as in between these faults. Overall, the SLRS faults are probably reactivated by the larger earthquakes (M ? 4.5) of the 20th century (CSZ in 1925; WQCSZ in 1935 and 1944; Saguenay in 1988) for which we have focal mechanisms. We propose that caution be exercised when linking historical events that have uncertain epicentres with SLRS faults. Similarly, SLRS faults should not be necessarily considered to be the reactivated structures for most small to moderate earthquakes (M defined NW-SE alignment with no obvious geological control, except perhaps, a hypothetical hotspot track. Two local factors can lead to the occurrence of SLRS earthquakes: weak faults or enhanced stress levels. We propose that local conditions, concentrated in a few seismic zones, can alter these factors and lead to the occurrence of earthquakes, especially those with M < 4.5. At a continent-wide scale, the correlation between the SLRS and earthquakes is appealing. We suggest, however, that pre-existing faults related to the SLRS do not explain all features of the seismicity. Seismicity is concentrated in more active areas, some with conspicuous normal faults and some with suspected weakening mechanisms such as intense pre-fracturing (e.g. due to a meteorite impact), the passage over a hot spot, or the presence of intrusions and lateral crustal density variations.

Lamontagne, M.; Ranalli, G.

2013-12-01

71

Location of geologic structures from interpretation of ERTS-1 imagery, Carbon County, Wyoming  

Science.gov (United States)

The author has identified the following significant results. Possible geologic structures in the basin sediments of Carbon County and vicinity were located by interpretation of ERTS-1 imagery. These same structures are not evident on existing conventional geologic maps of the area. Subsequent field checks confirmed much of the geologic interpretation, but revealed that two apparent closed structures identified on the ERTS-1 imagery were actually topographic pseudostructures in flat or homoclinal sediments. Stereoscopic coverage (where available) allows the interpreter to avoid such misinterpretations.

Marrs, R. W.; Barton, R.

1974-01-01

72

Geological Structures of the South Okinawa Trough based on Seismic Reflection Data  

Science.gov (United States)

The Southern Okinawa Trough (SOT) located offshore northeastern Taiwan is an extensional basin north of the Ryukyu Island Arc that opens toward Taiwan. In order to better understand the geological processes in the Southern Okinawa Trough, we collect all the available multi-channel seismic reflection data, reprocess some of them to improve the data quality, and interpret 22 seismic reflection profiles. A structural map, which shows the distribution of fault structures and submarine volcanoes in the study area, is compiled with the aid of seismic sequence analysis. We found that normal faults developed in both the northern and southern flanks of the SOT, and also in the axial area where volcanic extrusions are abundant, suggesting that the SOT is presently undergoing active extension. Some deeply rooted compressional structures are observed below the younger normal faults, which may indicate that the area offshore northern Taiwan was once in a convergent tectonic environment. We use seismic and bathymetry data to discuss the fault activities and related tectonic processes, also examine the volcanic activities and their geological environment.

Fan, M.; Liu, C.; Teng, L. S.

2011-12-01

73

Detailed fault structures in the Tarutung geothermal area derived from seismology and structural geology  

Science.gov (United States)

The oblique convergence between the Indo-Australian and Eurasian plates producing the subduction zone beneath south Indonesia causes the presence of the approximately 1650 km of dextral strike slip Sumatra fault (SF). The SF is segmented into 19 major sections featuring also pull-apart basins with different characteristics. One of the pull-apart basins along SF is the Tarutung basin located just south of the Toba caldera. We present the fault structure in the Tarutung geothermal area derived from seismological studies and supported by geological analysis. This information allows conclusions on the tectonic control of the geothermal system. The knowledge on the pattern of the fault system is highly beneficial to constrain prospective locations used in future exploitation. We detected the direct P and S wave arrivals of earthquakes recorded by a ten month deployment of 42 seismic stations in the Tarutung region. We relocated 809 events recorded by at least 8 stations with azimuthal gap angle less than 180 degrees by using 1D inversion for velocity structure and hypocenter locations (VELEST). The best solutions of VELEST are then used as the initials for the 3D inversion (SIMUL2000) to determine the 3D velocity models and more accurate earthquake locations. The seismicity distribution obtained from SIMUL2000 is compared with the earthquake locations obtained by the double difference relocation scheme (HYPODD) where 36,819 travel times and 766 waveform cross-correlations were involved. We analyzed the focal mechanisms for events having at least 11 clear first arrival polarities by using FPFIT. Surface structural study, measured striations and joints at 20 sites in the region, provide additional constraints on the deformation at shallower depth. South of the Tarutung basin, the seismicity distribution is well aligned to the main SF. The focal mechanisms show strike-slip behavior in agreement with the large-scale pattern of the SF. The application of HYPODD relocated the events even sharper and more focused. Along the Tarutung basin, the seismicity broadens and reveals interesting features. The seismicity aligned with the NW-SE main SF is mostly strike-slip with some normal component. The seismicity pattern shows some branches with normal faulting striking NE-SW crossing the main SF and the Tarutung basin. The pattern of seismicity and the focal mechanism provides evidence for the presence of the extensional duplex in the Tarutung area along the releasing bend of the SF. The fractures in NNW-SSE to NE-SW direction are notable from structural geology studies in the Tarutung area indicating conjugate synthetic and antithetic Riedel shears under compression at high angle to the NW-SE striking of SF System. The normal faulting trending SW-NE seems to be a preferred pathway of fluid flow. The dilatational zone as caused by clockwise rotation in a dextral simple shear induces dilation jog which may enhance the permeability in this part of the geothermal system.

Muksin, U.; Nukman, M.; Haberland, C. A.; Bauer, K.

2013-12-01

74

Neutron activation analysis of minerals from Cuddapah basin geological formations  

International Nuclear Information System (INIS)

Green and yellow serpentines along with two associated minerals namely dolomite and intrusive rock dolerite obtained from the asbestos mines of Cuddapah basin, Andhra Pradesh, India were analyzed by k0-based neutron activation analysis (k0-NAA) method. Gold (197Au) was used as the single comparator. Two reference materials namely USGS W-1 (geological) and IAEA Soil-7 (environmental) were analyzed as control samples to evaluate the accuracy of the method. A total of 21 elements present at major, minor and trace concentrations were determined in serpentines as well as associated minerals. The elemental concentrations were used for distinguishing and characterizing these minerals, and also to understand the extent of segregation of elements from the associated or host mineral rocks to serpentines. (author)

75

Radioactive waste disposal process geological structure for the waste disposal  

International Nuclear Information System (INIS)

The process described here consists to carry out the two phases of storage operation (intermediate and definitive) of radioactive wastes (especially the vitrified ones) in a geological dispositif (horizontal shafts) at an adequate deepness but suitable for a natural convection ventilation with fresh air from the land surface and moved only with the calorific heat released by the burried radioactive wastes when the radioactive decay has reached the adequate level, the shafts are totally and definitely occluded

76

The advanced scenario analysis for performance assessment of geological disposal  

International Nuclear Information System (INIS)

First of all, with regard to the FEP information data on the Engineered Barrier System (EBS) developed by JNC, description level and content of the FEPs have been examined from various angles on the basis of the latest research information. Each content of the FEP data has been classified and modified by means of integrating descriptive items, checking detail levels and correlations with other FEPs, collating with the H12 report, and adding technical information after H12 report. Secondly, scenario-modeling process has been studied. The study has been conducted by evaluating representation of the repository system, definition of FEP properties, and process interactions based on the concept of the interaction matrix (RES format) which represents influences between physicochemical characteristics of the repository, followed by an experimental development of the actual RES interaction matrix based on the H12 report as the examination to improve the transparency, traceability and comprehensibility of the scenario analysis process. Lastly, in relation to the geological disposal system, assessment techniques have been examined for more practical scenario analysis on particularly strong perturbations. Possible conceptual models have been proposed for each of these scenarios; seismic, faulting, and dike intrusion. As a result of these researches, a future direction for advanced scenario analysis on performance assessment has been indicated, as well as associated issues to be discussed have been clarified. (author)

77

Analysis of integrated geologic data for uranium exploration in Egypt  

International Nuclear Information System (INIS)

Geologic information system (GIS) related to Nuclear Raw Materials is in current development in the Scient. Inform. Dept. (NMC). Processing of data follows developed criteria in U-exploration. Landsat image interpretation, photo lineaments, field measured joints, faults, folds, foliation, lineation, and deformed pebbles when properly integrated and computerized have pointed out a comprehensive tectonic model related to the CED of Egypt. The area seemed to be subjected to three deformative stages, in the first two; rocks undergone plastic deformation, while in the third one, rocks failed in brittle mode where the Red Sea Transverse Tectonic Trend (ENE-WSW) was developed intersecting the older plastically developed linear elements (NW-SE). Further rejuvenations permit opening the mentioned fractures and occupied by siliceous materials and jasperoid veins and lastly by U-type mineralization, best depicted in the plutons of El Missikat, El Erediya, Um Had and Kab Amiri. The Oligocene Qatrani Formation, north of Lake Qarun, NWD of Egypt is a typical example of fluviatile deposits. The middle clayey member is enclosed between two porous sandy members. The carbonaceous shale related to the clayey member shows abnormal U-concentrations. Statistical analysis of the distribution of uranium and other trace elements in the carbonaceous shale shows that U, Y, Mn and Ca obey the lognormal law while Sr, Rb, Zr, Cr and Ti obey the normal law. A geologic factor is derived that normally distributed elements are stationary, indigenous probably of detrital origin. Meanwhile, other lognormally distributed elements are active and mobile. Subsurface mapping shows that uranium tends to concentrate in the troughs of the flexured carbonaceous shale suggesting an epigenetic origin. 14 refs, 9 figs, 4 tabs

78

Research and development of methods and technologies for CO2 capture in fossil fuel power plants and storage in geological formations in the Czech Republic, stage E4: Risk analysis. Risk analysis methods for CO2 storage in geological structures. Revision 0  

International Nuclear Information System (INIS)

The basis for any treatment of this issue is European Directive 2009/31/EC on the geological storage of carbon dioxide. It is demonstrated that the principles of underground storage of radioactive waste can be applied to the storage of CO2, and the same assessment tools, including mathematical models, can be used or modified. (P.A.)

79

Formation of secondary phases during deep geological final disposal of research reactor fuel elements. Structure and phase analysis; Bildung von sekundaeren Phasen bei tiefengeologischer Endlagerung von Forschungsreaktor-Brennelementen. Struktur- und Phasenanalyse  

Energy Technology Data Exchange (ETDEWEB)

For the assessment of a confident und sustainable final disposal of high level radioactive waste - fuel elements of german research reactors also account for such waste - in suitable, deep geological facilities, processes of the alteration of the disposed of waste and therefore the formation of the corrosion products, i. e. secondary phases must be well understood considering an accident scenario of a potential water inflow. In order to obtain secondary phases non-irradiated research reactor fuel elements (FR-BE) consisting of UAl{sub x}-Al were subjected to magnesium chloride rich brine (brine 2, salt repository) and to clay pore solution, respectively and furthermore of the type U{sub 3}Si{sub 2}-Al were solely subjected to magnesium chloride rich brine. Considering environmental aspects of final repositories the test conditions of the corrosion experiments were adjusted in a way that the temperature was kept constant at 90 C and a reducing anaerobic environment was ensured. As major objective of this research secondary phases, obtained from the autoclave experiments after appropriate processing and grain size separation have been identified and quantified. Powder X-ray diffraction (PXRD) and the application of Rietveld refinement methods allowed the identification of the corrosion products and a quantitative assessment of crystalline and amorphous contents. Scanning and transmission electron microscopy were additionally applied as a complementary method for the characterisation of the secondary phases. The qualitative phase analysis of the preprocessed secondary phases of the systems UAl{sub x}-Al and U{sub 3}Si{sub 2}-Al in brine 2 shows many similarities. Lesukite - an aluminium chloro hydrate - was observed for the first time considering the given experimental conditions. Further on different layered structures of the LDH type, iron oxyhydroxide and possibly iron chlorides, uncorroded residues of nuclear fuel and elementary iron were identified as well. Depending on preceding preparation procedures of the secondary phases the phase mixture resulted in different constituents. By preparation in water the stable phases obtained were aluminium hydroxides and not lesukite. Crystalline phases containing silicon were solely observed in the system U{sub 3}Si{sub 2}-Al in brine 2 being prepared with water. Contrary to these observations the system UAl{sub x}-Al in Mont Terri solution (clay pore water) qualitatively exhibits distinct different phase contents. Goethite, gypsum, hemi hydrate (bassanite), and accessory hematite were the only crystalline phases observed. Additionally aluminium and UAl{sub 4} as residues of nuclear fuel were also found. Considering the quantification of the brine 2 systems many common observations could be made. With respect to the corrosion products of UAl{sub x}-Al und U{sub 3}Si{sub 2}-Al prepared with isopropanol, lesukite and LDH compounds are the most abundant phases. The amorphous content, elemental iron and uncorroded residues of the nuclear fuel are mainly enriched in the coarse grain size fraction > 63 ?m. The water treatment of the secondary phases resulted in much less yield of solids. Quantitatively aluminium hydroxides exhibited the highest abundance. Clear differences could be observed in the system UAl{sub x}-Al in Mont Terri solution in view of the fact that the amorphous phases show the highest content of the corrosion products. The secondary phases could retain radioactive isotopes on the one hand by in situ formation and on the other hand by additionally being placed into stock as backfill, respectively. As special objective for assessing the potential of retention the amount of incorporation of europium into the crystal lattice of LDH compounds has also been investigated. Up to 20 mole percent considering the amount of aluminium were substituted by inactive europium acting as a trivalent simulant homologue for actinides. The refinement of the lattice parameters clearly indicated a linear relationship between the increase of the europium amount and the increase of the latt

Neumann, Andreas

2012-07-01

80

Structural geology of the North and Middle Caspian sea on the new geophysical data interpretation  

International Nuclear Information System (INIS)

Full text:A structural and tectonic map of the North and Middle Caspian Sea is made on the basis of seismic and other geological and geophysical data analysis. According to the plotting results the total amplitude range of the heterogeneous basement depths are in the North Caspian Sea (Ukatnensky depression-over 12 km and Prorva depression-over 16 km). In the middle Caspian Sea the deppest basement point is supposed in Sulak basin (over 12 km). The least basement depths are marked in Karpinsky ridge,Buzachinky and Karabogazsky arches (1-3 km). On the whole the morphology and structure of the basement confirms the conclusion previously made by many researches that the Caspian Sea is a heterogeneous depression superimposed on the junction of regional tectonic elements of various ages.The ancient East-European platform represented by Pricaspiisky depression (Donetsko-Astrakhanskaya fault system limits the latter in the south) is situated on the North. The middle Caspian Sea is occupied with the offshore continuation of Terek-Caspian foredeep is represented by Sulak basin clearly limited in the south by a system of upthrusts and thrusts falling under North Caucasus foreland.Geological interpretation of the Yuzhmorgeologiya Center new geophysical data allows making an assumption about the biohermexistence within TriassicSea sediments on Kuma-Manychsky depression offshore continuation. Seismic exploration works show strike-slip faults and thrust structure development withints and thrust structure development within the sedimentary cover on the offshore continuation of Karpinsky ridge.Some strike-slipped blocks are separated by left-side shifts of the northeast stretch.The pool location at the left-side (east) blocks of the shift areas is marked.

 
 
 
 
81

Investigation of structural geology and coal mine subsidence potential in Colorado Springs area using remote sensing and GIS technology  

International Nuclear Information System (INIS)

The purpose of this paper is to determine the extent to which remote structures which may affect the location and migration of subsidence over abandoned underground coal mines in the Colorado Springs area. Ultimately, these techniques could be useful for identifying such geologic structures at other abandoned mine land (AML) sites. Landsat satellite images and aerial photographs were used to interpret the geologic structure of the area. A geographic information system (GIS) was used to integrate the diverse data sets involved in the study and to allow reliable and reproducible spatial registration and analysis of the data. The specific study area used was the northern and northeastern Colorado Springs, Colorado, area where coal mining was active from the 1870s until 1957. The results of this study indicate that the subsidence hazard zones projected by Dames and Moore (1985) could be modified to take into account geologic structures as identified through remote sensing. Other AML sites should be investigated through remote sensing and lineament analysis to aid in fully evaluating subsidence potential of the sites. The GIS database also will provide a reasonably reliable source of spatial data for future land-use planning and tracking of subsidence hazards

82

ANALYSIS OF THE U. S. GEOLOGICAL SURVEY STREAMGAGING NETWORK.  

Science.gov (United States)

This paper summarizes the results from the first 3 years of a 5-year cost-effectiveness study of the U. S. Geological Survey streamgaging network. The objective of the study is to define and document the most cost-effective means of furnishing streamflow information. In the first step of this study, data uses were identified for 3,493 continuous-record stations currently being operated in 32 States. In the second step, evaluation of alternative methods of providing streamflow information, flow-routing models, and regression models were developed for estimating daily flows at 251 stations of the 3,493 stations analyzed. In the third step of the analysis, relationships were developed between the accuracy of the streamflow records and the operating budget. The existing streamgaging networks in four Districts were further analyzed to determine the impacts that satellite telemetry would have on the cost effectiveness. Satellite telemetry was not found to be cost effective on the basis of hydrologic-data collection alone, given present cost of equipment and operation.

Scott, Arthur, G.

1986-01-01

83

Seismic hazards: New trends in analysis using geologic data  

International Nuclear Information System (INIS)

In the late 1960s and early 1970s, largely in response to expansion of nuclear power plant siting and issuance of a code of federal regullations by the Nuclear Regulatory Commission referred to as Appendix A-10CFR100, the need to characterize the earthquake potential of individual faults for seismic design took on greater importance. Appendix A established deterministic procedures for assessing the seismic hazard at nuclear power plant sites. Bonilla and Buchanan, using data from historical suface-faulting earthquakes, developed a set of statistical correlations relating earthquake magnitude to surface rupture length and to surface displacement. These relationships have been refined and updated along with the relationship between fault area and magnitude and seismic moment and moment magnitude have served as the basis for selecting maximum earthquakes in a wide variety of design situations. In the paper presented, the authors discuss new trends in seismic hazard analysis using geologic data, with special emphasis on fault-zone segmentation and recurrence models and the way in which they provide a basis for evaluating long-term earthquake potential

84

Geological characterization of Ia volcanic structure, Boyaca - Colombia  

International Nuclear Information System (INIS)

Iza volcanic structure (5 grades 36 minutes 20 seconds N; 72 grades 59 minutes 33 seconds W) is the result of rising riodacitic to ryolithicmagmatic pulses, which didn't reach the surface, the first of them giving origin to intrusive breccias, interpreted as the result of indirect hot deep magma interaction with a sedimentary aquifer, leading to vapor overpressure and consequent fragmentation of the host rocks. The intrusive breccia form the southern part of the Iza edifice, it is massive beige to light red in color, locally with pseudo columnar joint; it is composed by angular to sub rounded sedimentary and minor igneous rock fragments in a porphyry rhyolitic matrix. This stage is followed by dome emplacement which a riodacitic to rhyolitic in composition. Petrographic analysis shows that they are similar to the matrix breccia; they have a porphiritic texture, phenocrist of sanidine, quartz and plagioclase and glassy matrix. Locally the domes are fractured presenting breccia facies (auto breccia and jig saw breccias, among others). Relationship with the host rock allow to interpreting the volcanic body as a cryptodomes, outcropping at surface by faulting and erosion.

85

Geological assessment for the new road leading into Lanjarón (Granada, Spain): slope stability analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Detailed geological study of the western part of a new road leading to Lanjarón (Betic Cordillera) has revealed the existence ofnatural instabilities in metapelitic rock masses ofthe Alpurrides Units. We have analysed the stability of the future slopes in the Cerro de la Escolta based on detailed geological mapping and measurement of structural data and mechanical discontinuities

Alonso Chaves, Francisco Manuel; Garci?a Navarro, Encarnacio?n; Gavila?n Guzma?n, Susana Mari?a; Va?zquez, Jorge; Camacho Cerro, Manuel Alejandro; Mantero, Isabel

2010-01-01

86

Hands-On Exercise in Environmental Structural Geology Using a Fracture Block Model.  

Science.gov (United States)

Describes the use of a scale analog model of an actual fractured rock reservoir to replace paper copies of fracture maps in the structural geology curriculum. Discusses the merits of the model in enabling students to gain experience performing standard structural analyses. (DDR)

Gates, Alexander E.

2001-01-01

87

Automated analysis of carbon in powdered geological and environmental samples by Raman spectroscopy.  

Science.gov (United States)

Raman spectroscopy can be used to assess the structure of naturally occurring carbonaceous materials (CM), which exist in a wide range of crystal structures. The sources of these geological and environmental materials include rocks, soils, river sediments, and marine sediment cores, all of which can contain carbonaceous material ranging from highly crystalline graphite to amorphous-like organic compounds. In order to fully characterize a geological sample and its intrinsic heterogeneity, several spectra must be collected and analyzed in a precise and repeatable manner. Here, we describe a suitable processing and analysis technique. We show that short-period ball-mill grinding does not introduce structural changes to semi-graphitized material and allows for easy collection of Raman spectra from the resulting powder. Two automated peak-fitting procedures are defined that allow for rapid processing of large datasets. For very disordered CM, Lorentzian profiles are fitted to five characteristic peaks, for highly graphitized material, three Voigt profiles are fitted. Peak area ratios and peak width measurements are used to classify each spectrum and allow easy comparison between samples. By applying this technique to samples collected in Taiwan after Typhoon Morakot, sources of carbon to offshore sediments have been identified. Carbon eroded from different areas of Taiwan can be seen mixed and deposited in the offshore flood sediments, and both graphite and amorphous-like carbon have been recycled from terrestrial to marine deposits. The practicality of this application illustrates the potential for this technique to be deployed to sediment-sourcing problems in a wide range of geological settings. PMID:23816131

Sparkes, Robert; Hovius, Niels; Galy, Albert; Kumar, R Vasant; Liu, James T

2013-07-01

88

Finite Element Stress Analysis of Spent Nuclear Fuel Disposal Canister in a Deep Geological Repository  

Science.gov (United States)

This paper presents the finite element stress analysis of a spent nuclear fuel disposal canister to provide basic information for dimensioning the canister and configuration of canister components and consequently to suggest the structural analysis methodology for the disposal canister in a deep geological repository which is nowadays very important in the environmental waste treatment technology. Because of big differences in the pressurized water reactor (PWR) and the Canadian deuterium and uranium reactor (CANDU) fuel properties, two types of canisters are conceived. For manufacturing, operational reasons and standardization, however, both canisters have the same outer diameter and length. The construction type of canisters introduced here is a solid structure with a cast insert and a corrosion resistant overpack. The structural stress analysis is carried out using a finite element analysis code, NISA, and focused on the structural strength of the canister against the expected external pressures due to the swelling of the bentonite buffer and the hydrostatic head. The canister must withstand these large pressure loads. Consequently, canisters presented here contain 4 PWR fuel assemblies and 33×9 CANDU fuel bundles. The outside diameter of the canister for both fuels is 122cm and the cast insert diameter is 112cm. The total length of the canister is 483cm with the lid/bottom and the outer shell of 5cm.

Kwon, Young Joo; Choi, Jong Won

89

The influence of geological loading on the structural integrity of an underground nuclear waste repository  

International Nuclear Information System (INIS)

Stresses are developed in underground nuclear waste repositories as a result of applied loads from geological movements caused by the encroachment of ice sheets or seismic activity for example. These stresses may induce fracturing of the waste matrix, repository vault and nearfield host geology. This fracturing will enhance the advective flow and allow more-rapid transfer of radionuclides from their encapsulation through the repository barriers and nearfield host rock. Geological loads may be applied either gradually as in crustal folding or encroachment of ice sheets, or rapidly as in the case of seismic movements. The analysis outlined in this report is conducted with a view to including the effects of geological loading in a probabilistic repository site assessment computer code such as SYVAC. (author)

90

Linking geology and microbiology: inactive pockmarks affect sediment microbial community structure.  

Science.gov (United States)

Pockmarks are geological features that are found on the bottom of lakes and oceans all over the globe. Some are active, seeping oil or methane, while others are inactive. Active pockmarks are well studied since they harbor specialized microbial communities that proliferate on the seeping compounds. Such communities are not found in inactive pockmarks. Interestingly, inactive pockmarks are known to have different macrofaunal communities compared to the surrounding sediments. It is undetermined what the microbial composition of inactive pockmarks is and if it shows a similar pattern as the macrofauna. The Norwegian Oslofjord contains many inactive pockmarks and they are well suited to study the influence of these geological features on the microbial community in the sediment. Here we present a detailed analysis of the microbial communities found in three inactive pockmarks and two control samples at two core depth intervals. The communities were analyzed using high-throughput amplicon sequencing of the 16S rRNA V3 region. Microbial communities of surface pockmark sediments were indistinguishable from communities found in the surrounding seabed. In contrast, pockmark communities at 40 cm sediment depth had a significantly different community structure from normal sediments at the same depth. Statistical analysis of chemical variables indicated significant differences in the concentrations of total carbon and non-particulate organic carbon between 40 cm pockmarks and reference sample sediments. We discuss these results in comparison with the taxonomic classification of the OTUs identified in our samples. Our results indicate that microbial communities at the sediment surface are affected by the water column, while the deeper (40 cm) sediment communities are affected by local conditions within the sediment. PMID:24475066

Haverkamp, Thomas H A; Hammer, Øyvind; Jakobsen, Kjetill S

2014-01-01

91

Constructing a large-scale 3D Geologic Model for Analysis of the Non-Proliferation Experiment  

Energy Technology Data Exchange (ETDEWEB)

We have constructed a regional 3D geologic model of the southern Great Basin, in support of a seismic wave propagation investigation of the 1993 Nonproliferation Experiment (NPE) at the Nevada Test Site (NTS). The model is centered on the NPE and spans longitude -119.5{sup o} to -112.6{sup o} and latitude 34.5{sup o} to 39.8{sup o}; the depth ranges from the topographic surface to 150 km below sea level. The model includes the southern half of Nevada, as well as parts of eastern California, western Utah, and a portion of northwestern Arizona. The upper crust is constrained by both geologic and geophysical studies, while the lower crust and upper mantle are constrained by geophysical studies. The mapped upper crustal geologic units are Quaternary basin fill, Tertiary deposits, pre-Tertiary deposits, intrusive rocks of all ages, and calderas. The lower crust and upper mantle are parameterized with 5 layers, including the Moho. Detailed geologic data, including surface maps, borehole data, and geophysical surveys, were used to define the geology at the NTS. Digital geologic outcrop data were available for both Nevada and Arizona, whereas geologic maps for California and Utah were scanned and hand-digitized. Published gravity data (2km spacing) were used to determine the thickness of the Cenozoic deposits and thus estimate the depth of the basins. The free surface is based on a 10m lateral resolution DEM at the NTS and a 90m lateral resolution DEM elsewhere. Variations in crustal thickness are based on receiver function analysis and a framework compilation of reflection/refraction studies. We used Earthvision (Dynamic Graphics, Inc.) to integrate the geologic and geophysical information into a model of x,y,z,p nodes, where p is a unique integer index value representing the geologic unit. For seismic studies, the geologic units are mapped to specific seismic velocities. The gross geophysical structure of the crust and upper mantle is taken from regional surface-wave studies. For regional seismic simulations we convert this realistic geologic model into elastic parameters. Upper crustal units are treated as seismically homogeneous while the lower crust and upper mantle are parameterized by a smoothly varying velocity profile. In order to mitigate spurious reflections, the lower crust and upper mantle are treated as velocity gradients as a function of depth.

Wagoner, J; Myers, S

2008-04-09

92

Analysis of naturally produced technetium and plutonium in geologic materials.  

Science.gov (United States)

In uncontaminated natural materials, plutonium and technetium exist exclusively as products (daughters) of nuclear reactions in which uranium is the principal reactant (parent). Under conditions of chemical stability over geologic periods of time, the relative abundances of daughter and parent elements are fixed by the rates of nuclear reactions and the decay of the daughter radionuclide. The state of this nuclear secular equilibrium condition is the primary basis of the geochemical study of these elements in nature. Thus, it is critical that nuclear parent and daughter abundances are measured in the same sample. We have developed a quantitative procedure for measuring subpicogram quantities of plutonium and technetium in gram quantities of geologic matrices such as uranium ores. The procedure takes advantage of the aggressive properties of sodium peroxide/hydroxide fusion to ensure complete dissolution and homogenization of complex materials, the precision provided by isotope dilution techniques, and the extreme sensitivity offered by thermal ionization mass spectrometry. Using this technique, a quantitative aliquot can be removed for uranium analysis by isotope dilution thermal ionization mass spectrometry or ? spectrometry. Although the application of the procedure is unique, the analytical concepts may find more general application in studies of environmental contamination by nuclear materials. To assess the precision and accuracy of the analytical results, blanks and standards were analyzed routinely for a 1-year period to ensure quality control of our sample analyses. The average technetium blank is 5 ± 4 fg (n = 8), and that for plutonium is 0.17 ± 0.15 pg (n = 7). Thus, the detection limit for technetium (defined as 3 times the standard deviation of the average blank) is 11 fg, and that for plutonium is 0.44 pg. To assess the procedural precision, Canadian Reference Material BL-5 was analyzed routinely with samples. The results of seven replicate analyses for technetium in this standard reference material yield a technetium concentration of 59.0 fg/g, with a remarkably small standard deviation of 0.6 fg, 1.0% of the average value. The results of six replicate analyses for the concentration of plutonium in BL-5 give 1.012 pg/g, with an equally small standard deviation of 0.016, 1.6% of the average value. No direct measure of accuracy can be done on the technetium or plutonium analyses, because no standard reference material exists for these elements. To help constrain the accuracy of our measurements, equilibrium technetium/uranium and plutonium/uranium abundances were calculated using the nuclear reaction code MCNP. For technetium, such calculations are relatively insensitive to variations in model parameters, and measurements fall within a 21% high/low bias. For plutonium, the calculations are very sensitive to model parameters and hence inherently less precise. Indirectly, spike and isotope mix calibrations made from weighted quantities of certified isotopes (both technetium and plutonium) can be used to determine the bias of the measurement system for these elements. These calibrations show that the measurement system is biased by no more than ±1.5%. PMID:21639292

Dixon, P; Curtis, D B; Musgrave, J; Roensch, F; Roach, J; Rokop, D

1997-05-01

93

Analysis on geological condition for uranium-polymetal metallization in Bayangshan downfaulted volcanic basin in Xinbaerhuyouqi  

International Nuclear Information System (INIS)

Bayangale downfaulted volcanic basin locates in the same metallogenic area with Er Nuote orefield of Mongolia in China-Russia-Mongolia uranium-polymetal metallogenic belt, and has the similar geological conditions with the Streltsovskoye uranium orefield in Russian. Through investigating the basement, cover rock, uranium content of rocks, structure and uranium-polymetal mineralization in the areas, the basin was believed to bear the geologic structural setting and fairly good condition for volcanic-type uranium -polymetall mineralization. (authors)

94

Reliable Classification of Geologic Surfaces Using Texture Analysis  

Science.gov (United States)

Communication delays and bandwidth constraints are major obstacles for remote exploration spacecraft. Due to such restrictions, spacecraft could make use of onboard science data analysis to maximize scientific gain, through capabilities such as the generation of bandwidth-efficient representative maps of scenes, autonomous instrument targeting to exploit targets of opportunity between communications, and downlink prioritization to ensure fast delivery of tactically-important data. Of particular importance to remote exploration is the precision of such methods and their ability to reliably reproduce consistent results in novel environments. Spacecraft resources are highly oversubscribed, so any onboard data analysis must provide a high degree of confidence in its assessment. The TextureCam project is constructing a "smart camera" that can analyze surface images to autonomously identify scientifically interesting targets and direct narrow field-of-view instruments. The TextureCam instrument incorporates onboard scene interpretation and mapping to assist these autonomous science activities. Computer vision algorithms map scenes such as those encountered during rover traverses. The approach, based on a machine learning strategy, trains a statistical model to recognize different geologic surface types and then classifies every pixel in a new scene according to these categories. We describe three methods for increasing the precision of the TextureCam instrument. The first uses ancillary data to segment challenging scenes into smaller regions having homogeneous properties. These subproblems are individually easier to solve, preventing uncertainty in one region from contaminating those that can be confidently classified. The second involves a Bayesian approach that maximizes the likelihood of correct classifications by abstaining from ambiguous ones. We evaluate these two techniques on a set of images acquired during field expeditions in the Mojave Desert. Finally, the algorithm was expanded to perform robust texture classification across a wide range of lighting conditions. We characterize both the increase in precision achieved using different input data representations as well as the range of conditions under which reliable performance can be achieved. An ensemble learning approach is used to increase performance by leveraging the illumination-dependent statistics of an image. Our results show that the three algorithmic modifications lead to a significant increase in classification performance as well as an increase in precision using an adjustable and human-understandable metric of confidence.

Foil, G.; Howarth, D.; Abbey, W. J.; Bekker, D. L.; Castano, R.; Thompson, D. R.; Wagstaff, K.

2012-12-01

95

An engineering geological appraisal of the Chamshir dam foundation using DMR classification and kinematic analysis, southwest of Iran  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the results of engineering geological  investigations and rock mechanics studies carried out at the proposed Chamshir dam site. It is proposed that a 155 m high solid concrete gravity-arc dam be built across the Zuhreh River to the southeast of the city of Gachsaran in south-western Iran. The dam and its associated structures are mainly located on the Mishan formation. Analysis consisted of rock mass classification and a kinematic
analysis of the dam foundation's rock masses. The studies were carried out in the field and the laboratory. The field studies included geological mapping, intensive discontinuity surveying, core drilling and sampling for laboratory testing. Rock mass classifications were made in line with RMR and DMR classification for the dam foundation. Dam foundation analysis regarding stability using DMR classification and kinematic analysis indicated that the left abutment's rock foundation (area 2 was unstable for planar, wedge and toppling failure modes.

Torabi Kaveh Mehdi

2011-12-01

96

Comparison between radar data and geophysical, geological and hydrological borehole paramenters by multivariate analysis of data  

International Nuclear Information System (INIS)

The object of the present work is to study the correlation between radar reflectors and geophysical, geological and hydraulical parameters from the boreholes. An additional objective is to show what information can be gained by the borehole radar with respect to waterflow and geological structures in crystalline rock. The tool for making the data modelling is Multivariate Data Analysis (SIMCA). For the data modelling there are two algorithms available in the SIMCA software. One for Principal Component analysis and one for Partial Least Squares regression analysis (PLS and PLS2). The PLS method gives the best result for the purpose of correlation between radar intensity and other variables. The result from the Principal Components, PLS, and PLS2 analysis shows that the strongest correlations results in a division between highly fractured rock and low fractured rock at all sites. Also, PLS and PLS2 analysis show that there is a good correlation between high radar intensity and highly fractured rock in the boreholes at all sites. The correlation between radar intensity and hydraulic condictivity is more ambiguous. Two of the investigated sites. Stripa and Finnsjoen, exhibit good correlation between radar intensity and hydraulic condictivity, while the correlation at Aevroe is lower and at Saltsjoetunnel it is poor. Hydraulic conductivity was not included in the analysis of the Klipperaas data. The best correlaiton in the data from Klipperaas was obtained between radar intensity and fractured lithological contracts. The degree of correlation between radar intensity and lithological contacts at the other four sites was lower than for Klipperaas. (24 figs., 37 tabs., 30 refs)

97

The Results of Borehole Acoustic Imaging from a Granite in the Jihlava District, Czech Republic: Implications for Structural Geological Research  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents utilisation of the acoustic borehole imaging method within the frame of structural geology research. Acoustic borehole imaging is a useful tool describing borehole walls. The method allows an identification of various inhomogenieties along the borehole including fractures. Despite the more or less subjective nature of interpretation of the acoustic borehole imaging similar to other geophysical method interpretations, is a careful comparison of the interpreted fractures and the fractures observed on a core allows us to orient both core and fractures. Furthermore it is possible to determine direction of present kinematic indicators on the oriented core (and fracture planes. Identified fault planes and kinematic indicators are valuable information for structural geology research, particularly for paleostress analysis. The procedure described here was applied in the PDV-1 borehole drilled in the immediate vicinity of the quarry near the Panské Dubenky village, Jihlava district, Czech Republic, Europe. The results are consistent with previous standard structural geology research conducted in the quarry. 

Lucie Nováková

2012-08-01

98

A method of identifying social structures in siting regions for deep geological repositories in Switzerland  

International Nuclear Information System (INIS)

Acceptance is a key element in the site selection process for deep geological repositories for high-level and low and intermediate-level radioactive waste in Switzerland. Participation requirements such as comprehensive negotiation issues and adequate resources have thus been defined by the Swiss Federal Office of Energy (SFOE). In 2008, on the basis of technical criteria Nagra (National Cooperative for the Disposal of Radioactive Waste) proposed several potential areas for deep geological repositories. The number of potential areas will be narrowed down within the next few years. All municipalities within the planning perimeter (the area in which surface facilities can be realised) are affected and form the siting region. In order to ensure that the local population have their say in the forthcoming discussions, regional participation bodies including all municipalities within a siting region are being set up by the SFOE. Regional participation ensures that local interests, needs and values are taken into account in the site selection process. Assembling the regional participation bodies is therefore of great importance. Before such bodies can be formed, however, the various interests, needs and values have to be identified, and special attention has to be paid to long-term interests of future generations, as well as to non-organised and under-represented interests. According to the concept of proportional representation, the interests, needs and values that are identified and weighted by the local population are to be represented in the regional participation procedure. The aim of this study is to share a method of mapping existing social structures in a defined geographical area. This involves a combination of an analysis of socio-economic statistical data and qualitative and quantitative social research methods

99

Structural geology of the Kinsevere Copper Deposit, DRC  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Kinsevere mine is a copper deposit located in the Democratic Republic of Congo (DRC), within the Central African Copperbelt. This area is situated in the Katangan basin within the SE portion of the Lufilian Arc, which is a large, arcuate structure that extends from SE Angola, across the DRC, and into NW Zambia. The purpose of this study is to characterise the brittle deformation observed around the Kinsevere copper deposit to lead to an understanding of the deformation history of the area...

Kazadi Banza, Samuel-barry

2013-01-01

100

Geological Structures in the WaIls of Vestan Craters  

Science.gov (United States)

A compelling case can be made that Vesta is the parent asteroid for the howardite, eucrite and diogenite (HED) meteorites [1], although this interpretation has been questioned [2]. Generalized models for the structure of the crust of Vesta have been developed based on petrologic studies of basaltic eucrites, cumulate eucrites and diogenites. These models use inferred cooling rates for different types of HEDs and compositional variations within the clan to posit that the lower crust is dominantly diogenitic in character, cumulate eucrites occur deep in the upper crust, and basaltic eucrites dominate the higher levels of the upper crust [3-5]. These models lack fine-scale resolution and thus do not allow for detailed predictions of crustal structure. Geophysical models predict dike and sill intrusions ought to be present, but their widths may be quite small [6]. The northern hemisphere of Vesta is heavily cratered, and the southern hemisphere is dominated by two 400-500 km diameter basins that excavated deep into the crust [7-8]. Physical modeling of regolith formation on 300 km diameter asteroids predicts that debris layers would reach a few km in thickness, while on asteroids of Vesta's diameter regolith thicknesses would be less [9]. This agrees well with the estimated =1 km thickness of local debris excavated by a 45 km diameter vestan crater [10]. Large craters and basins may have punched through the regolith/megaregolith and exposed primary vestan crustal structures. We will use Dawn Framing Camera (FC) [11] images and color ratio maps from the High Altitude and Low Altitude Mapping Orbits (HAMO, 65 m/pixel; LAMO, 20 m/pixel) to evaluate structures exposed on the walls of craters: two examples are discussed here.

Mittlefehldt, David; Nathues, A.; Beck, A. W.; Hoffmann, M.; Schaefer, M.; Williams, D. A.

2014-01-01

 
 
 
 
101

THM coupling sensitivity analysis in geological nuclear waste storage  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A deep geological repository involving a multi-barrier system constitutes one of the most promising options to isolate high-level radioactive waste from the human environment. In order to certify the efficiency of waste isolation, it is essential to understand the behaviour of the confining geomaterials under a variety of environmental conditions. The efficiency of an Engineered Barrier System (EBS) is largely based on the complex behaviour of bentonite. To contribute to a better understandin...

Dupray, Fabrice; Li, Chao; Laloui, Lyesse

2013-01-01

102

Development of geological structure modeling technology based on regional tectonic process (Joint research)  

International Nuclear Information System (INIS)

The geological structure relates to the groundwater flow and the water chemistry, so it is needed to understand the geological features such as the material transfers in the rock. In addition, it is possible to apply its information to the design and the construction of the geological disposal system. Some of faults with northwest strike developed in and around the Mizunami Underground Research Laboratory (MIU) control groundwater flow. It has been pointed out that these faults were formed as a part of pull-apart structure formed by right lateral movement of the Tsukiyoshi fault distributed in the north of the MIU site. But the formational mechanism of these faults is still uncertain. In this joint research, the analogue experiment and the numerical simulation were used to restore the real geological structures. Then, the distribution of unconfirmed faults was forecasted based on the result. The paleo-stress analyses revealed an ancient deformation mechanism, and the formation timing was presumed in the regional tectonics. The results were adopted for the design of the analog experiment and the numerical simulation. (author)

103

Commentary of Uruguay geological structure - Present status of its mining activity  

International Nuclear Information System (INIS)

This work is about the geological structure of Uruguay and its mining activity. The Rio de la Plata socket basin and the Rivera crystalline island are the oldest geochronological structures in Uruguay. This unit represents the 60% of the crystalline field and belongs to the Uruguay orogenetic Precambrian cycle. In the north there are sedimentary rocks and granites of the Upper Precambrian period.The mining and processing of marble, granite, agate, amethyst and metallic minerals are declared of national interest

104

Structural geology investigation on Massif Central and Parisian Basin (France)  

Science.gov (United States)

The author has identified the following significant results. Band 5 gives the most information concerning the fracturing in the Massif Central and Parisian Basins. Band 6 and 7 show the fractures emphasized by forest boundaries and by the linear trace of water courses. The most remarkable information drawn from the preliminary investigation of two ERTS-1 images covering two different landscapes, a regular relief of shelving plateau bounded by cuestas having a sedimentary origin and a mountainous region built in crystalline and volcanic rocks, is that the deep structural elements under a thick sedimentary cover can be translated on the surface by indirect criteria. MSS imagery has permitted the Metz fault to be extended towards the west and shows clearly, through land use on the Rhone Valley fluvial deposit, the continuation towards the east of the carboniferous basin of St. Etienne.

Weecksteen, G. (principal investigator)

1973-01-01

105

An analysis of spatial relation predicates in U.S. Geological Survey feature definitions  

Science.gov (United States)

The Semantic Web uses a data model called a triple, which consists of a subject -predicate - object structure. When represented as triples, geospatial data require a spatial relation term to serve as the predicate linking two spatial features. This document summarizes the approaches and procedures used during the identification of spatial relationships common between topographic features using terms from topographic data standards. This project identified verb-predicate arguments that could be used in the creation of data triples and ontologies for The National Map of the U.S. Geological Survey and also investigated the possibility of deriving ontology from predefined textual definitions. The primary purpose of this report is to present the data used for subsequent analysis. A summary of terms organized by basic categories is provided.

Caro, Holly K.; Varanka, Dalia E.

2011-01-01

106

Natural pseudowollastonite: Crystal structure, associated minerals, and geological context  

Science.gov (United States)

Pseudowollastonite, an extremely rare constituent of ultrahigh-temperature combustion metamorphic and igneous rocks, has been found as a rock-forming mineral in Ca-rich paralava veins of Nabi Musa fossil mud volcano (Dead Sea area). Pseudowollastonite-bearing paralavas are the products of combustion metamorphism associated with spontaneous burning of methane. The melt began to crystallize at 1480-1500 °C about the ambient pressure. Pseudowollastonite enters two mineral assemblages: (1) rankinite, larnite, nagelschmidtite, wollastonite (1T), gehlenite-rich melilite, Ti-rich andradite, cuspidine, and fluorapatite; (2) parawollastonite (2M), wollastonite (1T), gehlenite-rich melilite, Ti-rich andradite, fluorellestadite. In this study we present the first single-crystal structure determination of natural pseudowollastonite. Pseudowollastonite from Nabi Musa dome is stoichiometric CaSiO3 and belongs to the most widespread four-layer polytype: a = 6.83556(10) Å, b = 11.86962(18) Å, c = 19.6255(3) Å, ? = 90.6805(13)°, V = 1592.21(4) Å3, space group C2/c. We argue that pseudowollastonite is so scarce in nature because its formation requires joint action of several uncommon factors: availability of hot melts of T > 1200 °C that bear free calcium but are poor in Mg and Fe (mostly as Fe3 +) and their crystallization in the shallow crust followed by quenching.

Seryotkin, Yurii V.; Sokol, Ella V.; Kokh, Svetlana N.

2012-03-01

107

Evaluation of structural behavior, geological and hydrogeological characteristics  

International Nuclear Information System (INIS)

This study suggests a quantitative evaluation method of joint roughness coefficient (JRC). It was accomplished by using several statistical parameters to the 10 standard profiles. The results show that some of these parameters (Root mean square gradient, Structure function, and Fractal dimension) are suitable to represent the roughness characteristics. With these selected parameters, further studys have succeeded to examine the variance upon scale effect. The result shows that the fractal dimension is the most correlated parameter of all to JRC. The modified empirical equation of shear strength by introducing fractal dimension to determine JRC was suggested. To prove its validity and to examine the applicable limit of the estimated strength by this equation, the values were compared to those obtained in laboratory works. The results show that the quantification procedure for JRC permits more reliable results when the scale effect is considered. The equation which relates normal stress to shear strength of natural joints developed in gneissic rocks is also suggested. This provides inexpensive method to evaluate rock mass porperty and it can be applied to usual engineering practice. (Author)

108

An analysis on uranium ore-forming geological conditions and prospecting direction of in Baishun orefield  

International Nuclear Information System (INIS)

Baishun orefield is located in the south of Zhuguang Massif. It is a rich and large uranium accumulation area with many uranium occurrences and belts, frequent magma activities and developed fractures. Through the analysis on uranium ore-forming geological conditions such as the regional geological background, massif and tectonic conditions etc. in the mining area, it is considered that magma activities center and poly-directional tectonic composite portion in Baishun orefield are the main prospecting direction in future. (authors)

109

Study of gamma ray analysis software's. Application to activation analysis of geological samples  

International Nuclear Information System (INIS)

A comparative evaluation of the gamma-ray analysis software VISPECT, in relation to two commercial gamma-ray analysis software packages, OMNIGAM (EG and G Ortec) and SAMPO 90 (Canberra) was performed. For this evaluation, artificial gamma ray spectra were created, presenting peaks of different intensities and located at four different regions of the spectrum. Multiplet peaks with equal and different intensities, but with different channel separations, were also created. The results obtained showed a good performance of VISPECT in detecting and analysing single and multiplet peaks of different intensities in the gamma-ray spectrum. Neutron activation analysis of the geological reference material GS-N (IWG-GIT) and of the granite G-94, used in a Proficiency Testing Trial of Analytical Geochemistry Laboratories, was also performed , in order to evaluate the VISEPCT software in the analysis of real samples. The results obtained by using VISPECT were as good or better than the ones obtained using the other programs. (author)

110

The growth of geological structures by repeated earthquakes, 1, conceptual framework  

Science.gov (United States)

In many places, earthquakes with similar characteristics have been shown to recur. If this is common, then relatively small deformations associated with individual earthquake cycles should accumulate over time to create geological structures. It is shown that existing models developed to describe leveling line changes associated with the seismic cycle can be adapted to explain geological features associated with a fault. In these models an elastic layer containing the fault overlies a viscous half-space with a different density. Fault motion associated with an earthquake results in immediate deformation followed by a long period of readjustment as stresses relax in the viscous layer and isostatic equilibrium is restored. The flexural rigidity of the crust (or the apparent elastic thickness) provides the main control of the width of a structure. The loading due to erosion and deposition of sediment determines the ratio of uplift to subsidence between the two sides of the fault. -Authors

King, G. C. P.; Stein, R. S.; Rundle, J. B.

1988-01-01

111

Seismicity and Geologic Structures Indubitable in Wadi Hagul, North Eastern Desert, Egypt  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Paleo and recent earthquakes have been recorded in Wadi Hagul area and its environs, which have left behind geologic structures of deformation preserved in exposed sedimentary rocks. To evaluate such deformation and surface break, different techniques and data types are used compromising image processing techniques, Geographic Information Systems (GIS), seismicity data, as well as, field investigation. The field investigation clarified that the study area is enriched with soft-sediment deform...

Seleem, Tarek A.; Aboulela, Hamdy A.

2011-01-01

112

Probabilistic Structural Analysis Program  

Science.gov (United States)

NASA/NESSUS 6.2c is a general-purpose, probabilistic analysis program that computes probability of failure and probabilistic sensitivity measures of engineered systems. Because NASA/NESSUS uses highly computationally efficient and accurate analysis techniques, probabilistic solutions can be obtained even for extremely large and complex models. Once the probabilistic response is quantified, the results can be used to support risk-informed decisions regarding reliability for safety-critical and one-of-a-kind systems, as well as for maintaining a level of quality while reducing manufacturing costs for larger-quantity products. NASA/NESSUS has been successfully applied to a diverse range of problems in aerospace, gas turbine engines, biomechanics, pipelines, defense, weaponry, and infrastructure. This program combines state-of-the-art probabilistic algorithms with general-purpose structural analysis and lifting methods to compute the probabilistic response and reliability of engineered structures. Uncertainties in load, material properties, geometry, boundary conditions, and initial conditions can be simulated. The structural analysis methods include non-linear finite-element methods, heat-transfer analysis, polymer/ceramic matrix composite analysis, monolithic (conventional metallic) materials life-prediction methodologies, boundary element methods, and user-written subroutines. Several probabilistic algorithms are available such as the advanced mean value method and the adaptive importance sampling method. NASA/NESSUS 6.2c is structured in a modular format with 15 elements.

Pai, Shantaram S.; Chamis, Christos C.; Murthy, Pappu L. N.; Stefko, George L.; Riha, David S.; Thacker, Ben H.; Nagpal, Vinod K.; Mital, Subodh K.

2010-01-01

113

Uncertainty and sensitivity analysis of radionuclide migration in porous geologic medium  

International Nuclear Information System (INIS)

3H and 90Sr from a selected LILW (low and intermediate level radioactive wastes) repository base are taken as a sample. Uncertainty of mathematical model on radionuclide migration in porous geologic medium are analyzed by using Latin hypercube sampling techniques for seven uncertain parameters about hydrology and radionuclide absorption. In addition, parameter sensitivity analysis is performed by Spearman's partial rank correlation analysis

114

Geologic and morphological structure of the Bell region (a photographic map of the surface of Venus, plate V-23)  

International Nuclear Information System (INIS)

Four geologic and morphological units have been distinguished within the plate: (1) relics of complexes predating the plains; (2) banded plains; (3) smooth plains; and (4) volcanic and tectonic complexes. The Bell rise includes several individual large volcanic structures. Besides, faults of different directions and meteorite craters have been interpreted. The history of the region's geological development has been briefly examined

115

3D geological structure of Le Danois basin (North Iberian Margin) between 3° and 5° W  

Science.gov (United States)

This study shows a 3D geological interpretation of Le Danois Basin from the analysis of a dense set of high quality seismic reflection profiles together with boreholes, well logs and previous studies. The available data were acquired for oil exploration purposes in the North Iberian Margin, an extensional margin, separated from the Armorican counterpart during the opening of the Bay of Biscay in the Mesozoic. This margin was moderately inverted during the Alpine orogeny, when the Cantabrian-Pyrenean realm was formed in the North of the Iberian Peninsula and the Bay of Biscay was partially closed. Well data compilation and correlation led to the recognition of different stratigraphic units. The average velocity was deduced from sonic log tests, allowing the correlation with the seismic horizons, in order to obtain a 3D geological model of the studied area. The results show a deep trench filled with a thick mesozoic sequence uncorfomably covered by the cenozoic materials. The stratigraphic sequences, distinguished by their reflectivity patterns, geometrical relationships and structural features, show evidence of the three main tectonic events: 1) the extensional regional period from Permian to Upper Cretaceous, whose main recognizable structures are normal faults and asymmetric basins, filled by the Upper Jurassic to Lower Cretaceous synrift deposits which uncorfomably overlays the Lower to Middle Jurassic prerift materials; 2) the Upper Cretaceous passive margin stage, depicted by the formation of constant thickness deposits; 3) the Alpine compressional period, when reverse faults and related folds were formed by the inversion and reactivation of the previous extensional ones, at the same time that the Oligocene to Middle Eocene synorogenic material were deposited in minor basins, and diapirs were squeezed. From the structural patterns and spatial distribution of the stratigraphic sequences, three main domains, limited by four major normal faults, can be differentiated: 1) the southernmost area, where a minor trench is formed in relationship with a major inverted normal fault. It is filled by a thick sequence of cenozoic synorogenic deposits which uncorfomably overlays the thin extensional one; 2) the Asturian basin, a deep and wide trench filled by a thick sequence of synrift deposits, with a maximum thickness of about 5000 meters at the depocenter, which gradually decreases up to 1000 meters towards the edges, covered by the synorogenic materials, with a maximum thickness of 500 meters in the syncline structures which gradually decrease towards the anticlines, formed as a result of the fault inversion and diapir squeezing; 3) Le Danois Basin, a minor graben located in the northernmost edge, limited by a major horst structure and Le Danois High. The extensional basins geometry and the thrust emplacement cause a gradual uplift of the basement and the sedimentary sequence towards Le Danois High, where local erosional truncations, onlap geometries and unconformable surfaces are developed within the cenozoic syntectonic deposit.

Cadenas, Patricia; Fernández-Viejo, Gabriela; Gallastegui, Jorge

2013-04-01

116

The geological nature of dark material on Vesta and implications for the subsurface structure  

Science.gov (United States)

Deposits of dark material appear on Vesta’s surface as features of relatively low-albedo in the visible wavelength range of Dawn’s camera and spectrometer. Mixed with the regolith and partially excavated by younger impacts, the material is exposed as individual layered outcrops in crater walls or ejecta patches, having been uncovered and broken up by the impact. Dark fans on crater walls and dark deposits on crater floors are the result of gravity-driven mass wasting triggered by steep slopes and impact seismicity. The fact that dark material is mixed with impact ejecta indicates that it has been processed together with the ejected material. Some small craters display continuous dark ejecta similar to lunar dark-halo impact craters, indicating that the impact excavated the material from beneath a higher-albedo surface. The asymmetric distribution of dark material in impact craters and ejecta suggests non-continuous distribution in the local subsurface. Some positive-relief dark edifices appear to be impact-sculpted hills with dark material distributed over the hill slopes. Dark features inside and outside of craters are in some places arranged as linear outcrops along scarps or as dark streaks perpendicular to the local topography. The spectral characteristics of the dark material resemble that of Vesta’s regolith. Dark material is distributed unevenly across Vesta’s surface with clusters of all types of dark material exposures. On a local scale, some craters expose or are associated with dark material, while others in the immediate vicinity do not show evidence for dark material. While the variety of surface exposures of dark material and their different geological correlations with surface features, as well as their uneven distribution, indicate a globally inhomogeneous distribution in the subsurface, the dark material seems to be correlated with the rim and ejecta of the older Veneneia south polar basin structure. The origin of the dark material is still being debated, however, the geological analysis suggests that it is exogenic, from carbon-rich low-velocity impactors, rather than endogenic, from freshly exposed mafic material or melt, exposed or created by impacts.

Jaumann, R.; Nass, A.; Otto, K.; Krohn, K.; Stephan, K.; McCord, T. B.; Williams, D. A.; Raymond, C. A.; Blewett, D. T.; Hiesinger, H.; Yingst, R. A.; De Sanctis, M. C.; Palomba, E.; Roatsch, T.; Matz, K.-D.; Preusker, F.; Scholten, F.; Russell, C. T.

2014-09-01

117

Self-Discovery of Structural Geology Concepts using Interactive 3D Visualization  

Science.gov (United States)

Mastering structural geology concepts that depend on understanding three-dimensional (3D) geometries and imagining relationships among unseen subsurface structures are fundamental skills for geologists. Traditionally these skills are developed first, through use of 2D drawings of 3D structures that can be difficult to decipher or 3D physical block models that show only a limited set of relationships on the surfaces of the blocks, followed by application and testing of concepts in field settings. We hypothesize that this learning process can be improved by providing repeated opportunities to evaluate and explore synthetic 3D structures using interactive 3D visualization software. We present laboratory modules designed for undergraduate structural geology curriculum using a self-discovery approach to teach concepts such as: the Rule of V’s, structure separation versus fault slip, and the more general dependence of structural exposure on surface topography. The laboratory modules are structured to allow students to discover and articulate each concept from observations of synthetic data both on traditional maps and using the volume visualization software 3DVisualizer. Modules lead students through exploration of data (e.g., a dipping layered structure exposed in ridge-valley topography or obliquely offset across a fault) by allowing them to interactively view (rotate, pan, zoom) the exposure of structures on topographic surfaces and to toggle on/off the full 3D structure as a transparent colored volume. This tool allows student to easily visually understand the relationships between, for example a dipping structure and its exposure on valley walls, as well as how the structure extends beneath the surface. Using this method gives students more opportunities to build a mental library of previously-seen relationships from which to draw-on when applying concepts in the field setting. These laboratory modules, the data and software are freely available from KeckCAVES.

Billen, M. I.; Saunders, J.

2010-12-01

118

Structural geology mapping using PALSAR data in the Bau gold mining district, Sarawak, Malaysia  

Science.gov (United States)

The application of optical remote sensing data for geological mapping is difficult in the tropical environment. The persistent cloud coverage, dominated vegetation in the landscape and limited bedrock exposures are constraints imposed by the tropical climate. Structural geology investigations that are searching for epithermal or polymetallic vein-type ore deposits can be developed using Synthetic Aperture Radar (SAR) remote sensing data in tropical/sub-tropical regions. The Bau gold mining district in the State of Sarawak, East Malaysia, on the island of Borneo has been selected for this study. The Bau is a gold field similar to Carlin style gold deposits, but gold mineralization at Bau is much more structurally controlled. Geological analyses coupled with the Phased Array type L-band Synthetic Aperture Radar (PALSAR) remote sensing data were used to detect structural elements associated with gold mineralization. The PALSAR data were used to perform lithological-structural mapping of mineralized zones in the study area and surrounding terrain. Structural elements were detected along the SSW to NNE trend of the Tuban fault zone and Tai Parit fault that corresponds to the areas of occurrence of the gold mineralization in the Bau Limestone. Most of quartz-gold bearing veins occur in high-angle faults, fractures and joints within massive units of the Bau Limestone. The results show that four deformation events (D1-D4) in the structures of the Bau district and structurally controlled gold mineralization indicators, including faults, joints and fractures are detectable using PALSAR data at both regional and district scales. The approach used in this study can be more broadly applicable to provide preliminary information for exploration potentially interesting areas of epithermal or polymetallic vein-type mineralization using the PALSAR data in the tropical/sub-tropical regions.

Pour, Amin Beiranvand; Hashim, Mazlan

2014-08-01

119

Neutron activation analysis of geological samples for gold and accessory elements power reactor  

International Nuclear Information System (INIS)

Possibility of using a power reactor for neutron activation analysis to detect gold and accompanying elements in geological samples of a region was investigated. Specimens (gold-containing samples and standards) were irradiated in a spare channel for ionization chambers located outside the core in graphite reflector. Spectrometry was conducted with the help of a semiconducting detector with LP 4900 multichannel analizer. Sensitivity threshold for gold was (1-3)10-6 % - (1-2)10-5 %. It is shown that this method can be used not only for gold detection but for high-sensitive multielement analysis of geological samples

120

Integration of geological information in a structured approach to development of a safety case  

International Nuclear Information System (INIS)

vides a unique challenge for ensuring transparency and traceability in development of conceptual site models which form a basis for repository concepts and associated safety cases in parallel with the step-wise siting process. A structured approach, therefore, is required to meet this target, which has been discussed partly in the light of development of Repository Concepts for given siting environments. The Siting Factors for selection of PIAs has also been developed. This paper illustrates a methodology for integrating geological information into the conceptual site models to be used in the structured approach. (author)

 
 
 
 
121

Structural analysis of DAEs  

DEFF Research Database (Denmark)

Differential algebraic equations (DAEs) constitute a fundamental model class for many modelling purposes in engineering and other sciences, especially for dynamical simulation of component based systems. This thesis describes a practical methodology and approach for analysing general DAE. The methodology is mainly based on strutural index analysis which is not limited by the index of the DAE as other methodologies. As a result of structural index analysis one can perform index reduction of the DAE and obtain the so-called augmented underlying ODE. It is also described, how to use the augmented underlying ODE for finding consistent initial values and solve the initial value problem for the original DAE. As a methodology for integrating the augmented underlying ODE, the dummy derivative method is investigated. The methodology avoids the traditional stability and drift-of problems of using the underlying ODE. The investigations concern the identification of quantities that can trigger the automatic choice of new dummy derivatives during integration. This is a practical problem that needs to be solved before implementations of the method are possible. The general methodology is tested in practice, by the implementation of the Simpy tool box. This is an object oriented system implemented in the Python language. It can be used for analysis of DAEs, ODEs and non-linear equation and uses e.g. symbolic representations of expressions and equations. The presentations of theory and algorithms for structural index analysis of DAE is original in the sense that it is based on a new matrix representation of the structural information of a general DAE system instead of a graph oriented representation. Also the presentation of the theory is found to be more complete compared to other presentations, since it e.g. proves the uniqueness of the structural index reduction process. Also included, is a discussion of criticism and defence of structural analysis.

Poulsen, Mikael Zebbelin

2002-01-01

122

Method of magnetic susceptibility mapping of drilled cores. Experimental measurements for geologic structures determination  

International Nuclear Information System (INIS)

The evaluation of the safety of a deep geologic repository for dangerous materials requires the knowledge of the interstitial system of the surrounding host rock. A method is proposed for the determination of geologic structures (in particular fractures) from the magnetic susceptibility mapping of drilled cores. The feasibility of the method has been demonstrated using a SQUID magneto-gradient meter. A measurement tool using a new magnetic susceptibility captor and a testing bench have been developed. This tool allows the measurement of rocks with a magnetic susceptibility greater than 10-5 SI units and can generate magnetic susceptibility maps with 4 x 4 mm2 pixels. A magnetic visibility criterion has been defined which allows to foresee if a structure is visible or not. According to the measurements done, it is shown that any centimeter-scale structure with a sufficient magnetic contrast (20%) with respect to the matrix is visible. Therefore, the dip and the orientation of such structure can be determined with a 3 degree and a 5 degree precision, respectively. The position of the structure along the core axis is known with a 4 mm precision. On the other hand, about half of the magnetic contrasts observed do not correspond to the visual analyses and can be explained by very small variations of the mineralogic composition. This last point offers some interesting ways for future research using magnetic susceptibility mapping. (J.S.). 31 refs., 90 figs., 18 tabs., 2 photos., 6 appends

123

Activation analysis of gold in geological samples (Paper No. RA-24)  

International Nuclear Information System (INIS)

The technique of neutron activation analysis (NAA) has been applied to study the distribution of gold in some geological samples. Traces of gold in the samples were preconcentrated in a solid matrix through a chemical procedure involving solvent extraction using MIBK and coprecipitation with PbS. Gold contents in the samples as determined by NAA vary from ppb to ppm levels. (author)

124

Automated grid generation from models of complex geologic structure and stratigraphy  

Energy Technology Data Exchange (ETDEWEB)

The construction of computational grids which accurately reflect complex geologic structure and stratigraphy for flow and transport models poses a formidable task. With an understanding of stratigraphy, material properties and boundary and initial conditions, the task of incorporating this data into a numerical model can be difficult and time consuming. Most GIS tools for representing complex geologic volumes and surfaces are not designed for producing optimal grids for flow and transport computation. We have developed a tool, GEOMESH, for generating finite element grids that maintain the geometric integrity of input volumes, surfaces, and geologic data and produce an optimal (Delaunay) tetrahedral grid that can be used for flow and transport computations. GEOMESH also satisfies the constraint that the geometric coupling coefficients of the grid are positive for all elements. GEOMESH generates grids for two dimensional cross sections, three dimensional regional models, represents faults and fractures, and has the capability of including finer grids representing tunnels and well bores into grids. GEOMESH also permits adaptive grid refinement in three dimensions. The tools to glue, merge and insert grids together demonstrate how complex grids can be built from simpler pieces. The resulting grid can be utilized by unstructured finite element or integrated finite difference computational physics codes.

Gable, C.; Trease, H.; Cherry, T.

1996-04-01

125

Potential structures for CO2 geological storage in the Baltic Sea: case study offshore Latvia  

Directory of Open Access Journals (Sweden)

Full Text Available This study is focused on two structures in the Baltic offshore region (E6 and E7 structures in Latvia prospective for the geological storage of carbon dioxide (CO2. Their CO2 storage capacities were estimated recently with different levels of reliability. Petrophysical, geophysical, mineralogical and geochemical parameters of reservoir rocks represented by quartz sandstones of the Deimena Formation of Middle Cambrian in two wells and properties of Silurian and Ordovician cap rocks were additionally studied and interpretedin the present contribution. Extended methodology on rock measurements and estimation of conservative and optimistic storage capacity are presented. Uncertainties and risks of CO2 storage in the offshore structure E6 estimated as the most prospective for CO2geological storage in the Baltic Region, and the largest among all onshore and offshore structures studied in Latvia, were discussed. We re-estimated the previous optimistic capacity of the E6 structure (265–630 Mt to 251–602 Mt. Considering fault system within the E6 structure we estimated capacity of two compartments of the reservoirseparately (E6-A and E6-B. Estimated by the optimistic approach CO2storage capacity of the E6-A part was 243–582 Mt (mean 365 Mt and E6-B part 8–20 Mt (mean 12 Mt. Conservative capacity was 97–233 Mt (mean 146 Mt in the E6-A, and 4–10 Mt (mean 6 Mt in the E6-B. The conservative average capacity of the E6-B part was in the same range as this capacity in the E7 structure (6 and 7 Mt respectively. The total capacity of the two structures E6 and E7, estimated using the optimistic approach was on average 411 Mt, and using the conservative approach, 159 Mt.

Kazbulat Shogenov

2013-07-01

126

TBR-2 structural analysis  

International Nuclear Information System (INIS)

This paper presents the structural analysis developed during the TBR-2 tokamak project studies. Starting with electromagnetic interaction forces on each, toroidal and poloidal coils many structural calculations have been carried out using locally developed usual E.M. interaction codes and a finite element method stress code. Following the analysis it has been determined that there is radially inward force of 1235 kN and overturning torque of 243 kNm acting on toroidal coils. This stress and displacements due to in plane loads have been calculated using a finite element code which show that the maximum stress of 240 MPa and displacement of 0.21 mm can be present at the inner part of the toroidal field coil. (Author)

127

Determination of gold and silver in geological standard samples MGI by instrument neutron activation analysis  

International Nuclear Information System (INIS)

Gold and silver in geological standard samples MGI were determined by instrument neutron activation analysis. The various interferences of nuclides were considered. Corrected factors of the geometry in different positions have been determined. Using the geological standard sample MGM and radiochemical separation neutron activation method as reference, the reliability of this method is proved. Gold content in samples is 0.4-0.009 g/t, silver content is 9-0.3 g/t. Standard deviation is less than 3.5%, the precision of the measurement is 4.8-11.6%

128

Instrumental neutron activation analysis of geological and pedological samples  

International Nuclear Information System (INIS)

A comparative study is presented on neutron activation analysis of rock and soil samples using whole reactor neutron spectrum and epithermal neutrons with both relative and monostandard procedures. The latter procedure used with epithermal neutron activation analysis of soil samples necessitated the use of the ''effective resonance integrals'' which were determined experimentally. The incorporation of the ? factor, representing deviation of reactor epithermal neutron flux from 1/E law, is developed. The main criteria for the choice of one or more of the procedures studied for a given purpose are also indicated. Analysis of 15 trace elements, Ca and Fe in the standard Japanese granite JC-1 using monostandard epithermal neutron activation gave results in good agreement with the average literature values. (author)

129

Determination of hafnium and zirconium in geological materials by neutron activation analysis  

International Nuclear Information System (INIS)

In this paper, neutron activation analysis was developed for determining hafnium and zirconium in geological materials. The USGS geological standard rocks GSP-1 (granodiorite) and W-1 (di abase). The Brazilian geological standards GB-1 (granite) and BB-1 (basalt) from Instituto de Geociencias da Universidade da Bahia and P-1 a uraniferous rock from Pocos de Caldas, MG, Brazil were analyzed. Hafnium present in these rocks was analyzed by purely instrumental method by irradiating with both thermal and epithermal neutrons from IEA-R1 nuclear research reactor. In the case of zirconium depending on the sample a radiochemical separation was required. 154 Eu and 152 Eu radioisotopes emit gamma rays with energies too close to those emitted by 95 Zr and they cause interferences. (author)

130

Summarized analysis on potential of uranium resources in China and strategy for uranium geologic exploration  

International Nuclear Information System (INIS)

Through the summarized analysis on the potential of uranium resources and the degree of uranium geologic work, the author proposes the strategy of uranium geologic exploration in China as follows: the Chinese government should make a long-term program for uranium geologic exploration and insist on the basic policy to be based on domestic resources, to meet the domestic demand, to increase of the storage (the increase of storage includes active utilization of uranium resources of foreign countries), and to do the uranium exploration properly in advance. Taking the ISL-amenable sandstone-hosted uranium deposit as the major prospecting target combined with actively exploring other types of economic uranium deposits should be taken as the basic exploration strategy. Guiding by new geologic-metallogenic theory system, using advanced exploration method and technique system, GIS prediction method system and digital geologic map series to do uranium exploration are regarded as basic technical idea to accelerate ascertaining potential uranium resources in China, and to provide powerful resources guarantee for the development of China's nuclear industry. (author)

131

Comparing Geologic Data Sets Collected by Planetary Analog Traverses and by Standard Geologic Field Mapping: Desert Rats Data Analysis  

Science.gov (United States)

Geologic mapping involves interpreting relationships between identifiable units and landforms to understand the formative history of a region. Traditional field techniques are used to accomplish this on Earth. Mapping proves more challenging for other planets, which are studied primarily by orbital remote sensing and, less frequently, by robotic and human surface exploration. Systematic comparative assessments of geologic maps created by traditional mapping versus photogeology together with data from planned traverses are limited. The objective of this project is to produce a geologic map from data collected on the Desert Research and Technology Studies (RATS) 2010 analog mission using Apollo-style traverses in conjunction with remote sensing data. This map is compared with a geologic map produced using standard field techniques.

Feng, Wanda; Evans, Cynthia; Gruener, John; Eppler, Dean

2014-01-01

132

Scientific Journals as Fossil Traces of Sweeping Change in the Structure and Practice of Modern Geology  

Science.gov (United States)

In our attempts to track changes in geological practice over time and to isolate the source of these changes, we have found that they are largely connected with the germination of new geologic subdisciplines. We use keyword and title data from articles in 68 geology journals to track the changes in influence of each subdiscipline on geology over…

Fratesi, Sarah E.; Vacher, H. L.

2008-01-01

133

Structured development of a petrophysics laboratory computer system to aid in formation evaluation and geologic interpretation  

Energy Technology Data Exchange (ETDEWEB)

Problem solving, data collection, and analysis in geology require diverse tools and methods. Computers must be convenient and versatile to be useful as laboratory apparatus and as tools for use in formation evaluation and geologic interpretation. Networking and distributed intelligence provide a laboratory with flexibility and power for cost-effective real-time data collection, management, and analysis. Networking facilities toolbox-style programming; improves data compilation, management, and comparison; and increases peripheral effectiveness. Distributed intelligence enhances local instrumentation, uninterrupted real-time data collector, and data analysis. The system presented includes facilities for instrumentation, data collection and management, and interpretation, analysis, and presentation for such systems as mercury injection, rock electrical properties, gas slippage, Klinkenberg correction, gamma-ray logging, cation exchange capacity, thermal neutron capture cross section, and permeability/porosity measurements. The individual systems share central text and graphic hard-copy devices and high-speed mass storage and backup facilities. Modifying the central system updates many of the remote system facilities such as user interfaces and graphic facilities. Individual system configurations include instrumentation, high-resolution color graphics, analog to digital conversion, and variation in computing power.

Hoyt, B.R.; Skopec, R.A. (Gearhart Industries, Inc., Fort Worth, TX (USA))

1987-02-01

134

First Paleomagnetic Map of the Easternmost Mediterranean Derived from Combined Geophysical-Geological Analysis  

Science.gov (United States)

he easternmost Mediterranean is a tectonically complex region evolving in the long term and located in the midst of the progressive Afro-Eurasian collision (e.g., Ben-Avraham, 1978; Khain, 1984). Both rift-oceanic systems and terrane belts are known to have been formed in this collision zone (Stampfli et al., 2013). Despite years of investigation, the geological-geophysical structure of the easternmost Mediterranean is not completely known. The formation of its modern complex structure is associated with the evolution of the Neotethys Ocean and its margins (e.g., Ben-Avraham and Ginzburg, 1990; Robertson et al., 1991; Ben-Avraham et al., 2002). The easternmost Mediterranean was formed during the initial phase of the Neotethys in the Early and Late Permian (Golonka and Ford, 2000; Stampfli et al., 2013). At present this block of the ocean crust situated in the northern part of the Sinai plate (Ben-Avraham, 1978; Eppelbaum et al., 2012, 2014) is object of our investigation. The easternmost Mediterranean region has attracted increasing attention in connection with the recent discoveries of significant hydrocarbon deposits in this region (e.g., Montadert et al., 2010; Schenk et al., 2010; Eppelbaum et al., 2012). For example, Schenk et al. (2010) consider that more than 4 trillion m3 of recoverable gas is available in the Levant Basin (which located in the central part of the easternmost Mediterranean). Currently seismic prospecting is the main tool used in hydrocarbon deposit discovery. However, even sophisticated seismic data analysis (e.g., Hall et al., 2005; Roberts and Peace, 2007; Gardosh et al., 2010; Marlow et al., 2011; Lazar et al., 2012), fails to identify the full complex structural-tectonic mosaic of this region, and more importantly, is unable to clarify its baffling complex tectonic evolution. This highlights the need for combined analysis of geophysical data associated with the paleomagnetic and paleobiogeographic conditions that can yield deep paleotectonic criteria for oil and gas discovery in this region. Extensive geological-geophysical investigations have been carried out in this region, and a significant number of deep boreholes have been drilled. However integrated estimation of the deep structure of the hydrocarbon host deposits and their space-time evolution in terms of the modern geodynamics (first of all, plate tectonics: Ben-Avraham and Ginzburg, 1990; Robertson, 1998; Ben-Avraham et al., 2002, 2006; Jimenez-Munt et al., 2003; Le Pichon and Kreemer, 2010), are comparatively recent (Eppelbaum and Katz, 2011, 2012a; Eppelbaum et al., 2012, 2014). We elucidate this geodynamic relationship by examining the structural floors within the following tectonic-geophysical zones: (1) regions of development of continental crust of the Nubian, Arabian and Sinai plates, (2) remaining oceanic crust of the eastern Mediterranean, and (3) the thinned continental crust of the terrane belt. A series of new gravity and magnetic maps developed by employing satellite and airborne data (as well their transformations) accompanied by tectonic schemes were constructed (Eppelbaum and Katz, 2011; Eppelbaum et al., 2012a, 2012b, 2014). These new maps are crucial to a better understanding of the dynamics of hydrocarbon basin formation within the continental and shelf depressions, as well as the deep depressions of the easternmost Mediterranean where gas deposits in zones of oceanic crust evolution have only recently (April 2013) begun to be exploited. Careful attention should be paid to the blocks of oceanic (basaltic) crust with reverse magnetization that were discovered (Ben-Avraham et al., 2002; Eppelbaum, 2006). This issue was very briefly (Eppelbaum and Katz, 2012a) explained as paleomagnetic Kiama zone of inverse polarity and demands separate consideration. An integrated magnetic-gravity-seismic analysis conducted along three interpretation profiles unambiguously indicates the presence of blocks of the Earth's crust with reverse magnetization (Ben-Avraham et al., 2002). The results of 3D magnetic field modeling (advanced G

Eppelbaum, Lev; Katz, Youri

2014-05-01

135

Influence of lithology and geologic structure on in situ stress: Examples of stress heterogeneity in reservoirs  

Energy Technology Data Exchange (ETDEWEB)

Knowledge of in situ stress is increasingly understood to be an important factor in formulating a multidisciplinary approach to reservoir characterization, and in the development and completion of oil and gas reservoirs. Two examples are presented to illustrate the influence of lithology and geologic structure on the distribution and heterogeneity of stress at depth. Stress measurements made in flat-lying, tight gas sandstone reservoirs and bounding mudstone formations of the Mesaverde Group in the Piceance Basin of Colorado show that principal horizontal stress magnitudes do not increase linearly with depth, solely as a function of the overburden, but vary with lithology. Minimum horizontal stresses in sandstone layers are more than 4 MPa less than adjacent mudstones. Stress measurements made in the Ekofisk Field in the North Sea demonstrate that principal horizontal stress directions are not uniform across a large structural dome, but are radial, with the azimuth of the maximum horizontal stress oriented perpendicular to the structural contours around the dome. These two examples indicate that in situ stress is not always defined by regional boundary conditions of a sedimentary basin, but is also affected by the local geological environment. 37 refs., 6 figs.

Teufel, L.W.

1989-01-01

136

Modified FILTERSIM Algorithm for Unconditional Simulation of Complex Spatial Geological Structures  

Directory of Open Access Journals (Sweden)

Full Text Available Facies and fracture network modeling need robust, realistic and multi scale methods that can extract and reproduce complex relations in geological structures. Multi Point Statistic (MPS algorithms can be used to model these high order relations from a visually and statistically explicit model, a training image. FILTERSIM as a pattern based MPS method attracts much attention. It decreases the complexity of computation, accelerates search process and increases CPU per-formance compare to other MPS methods by transferring training image patterns to a lower dimensional space. The results quality is not however as satisfactory. This work presents an improved version of FILTERSIM in which pattern extraction, persisting and pasting steps are modified to enhance visual quality and structures continuity in the realiza-tions. Examples shown in this paper give visual appealing results for the reconstruction of stationary complex struc-tures.

Mohammadreza Rasaei

2012-07-01

137

Non-destructive neutron activation analysis of gold in geological samples  

International Nuclear Information System (INIS)

A method of gold determination in geological samples by means of neutron activation analysis is described. This method is based on the 197Au(n,?)198Au nuclear reaction. The 411.8 keV gamma-ray of 198Au is measured by high-resolution Ge/HP/detector. Under typical analytical condition the sensitivity of the analysis is 0.1 ppm. (author). 7 refs., 1 fig., 2 tabs

138

Analysis of geological samples for gold and silver by the method of spectral ratios  

International Nuclear Information System (INIS)

The paper describes a gamma-ray activation analysis method for determining gold and silver in geological samples when the interfering elements, Hf, Ba, U, and Th, are also present. Spectral ratios and the correct choice of measuring windows are described. After testing the method on ore samples, the author concludes it is a quantitative analysis for a content of gold or silver of no less than 5 g/ton

139

Application of multiple-point geostatistics on modelling pumping tests and tracer tests in heterogeneous environments with complex geological structures  

Science.gov (United States)

In heterogeneous environments with complex geological structures, analysis of pumping and tracer tests is often problematic. Standard interpretation methods do not account for heterogeneity or simulate this heterogeneity introducing empirical zonation of the calibrated parameters or using variogram-based geostatistical techniques that are often not able to describe realistic heterogeneity in complex geological environments where e.g. sedimentary structures, multi-facies deposits, structures with large connectivity or curvi-linear structures can be present. Multiple-point geostatistics aims to overcome the limitations of the variogram and can be applied in different research domains to simulate heterogeneity in complex environments. In this project, multiple-point geostatistics is applied to the interpretation of pumping tests and a tracer test in an actual case of a sandy heterogeneous aquifer. This study allows to deduce the main advantages and disadvantages of this technique compared to variogram-based techniques for interpretation of pumping tests and tracer tests. A pumping test and a tracer test were performed in the same sandbar deposit consisting of cross-bedded units composed of materials with different grain sizes and hydraulic conductivities. The pumping test and the tracer test are analyzed with a local 3D groundwater model in which fine-scale sedimentary heterogeneity is modelled using multiple-point geostatistics. To reduce CPU and RAM requirements of the multiple-point geostatistical simulation steps, edge properties indicating the presence of irregularly-shaped surfaces are directly simulated. Results show that for the pumping test as well as for the tracer test, incorporating heterogeneity results in a better fit between observed and calculated drawdowns/concentrations. The improvement of the fit is however not as large as expected. In this paper, the reasons for these somewhat unsatisfactory results are explored and recommendations for future applications of multiple-point geostatistics on pumping tests and tracer tests are formulated.

Huysmans, Marijke; Dassargues, Alain

2014-05-01

140

Comparison of the SKI, SKB, and SKN geological and structural models of the Aespoe area  

International Nuclear Information System (INIS)

Three sets of geological and structural models produced by three different groups are compared. The same set of basic data has been available to each of the groups. The models, all of which are 2 by 2 km by 1 km deep - or smaller, are based entirely on surface-based investigations. The modelled area is centered on the island of Aespoe, where SKB has built the Hard Rock Laboratory (HRL) in plutonic bedrock at a depth of 500 m. SKB (Swedish Nuclear Fuel and Waste Management Co) has recorded the basic data during the period 1986 to 1991, before starting the underground work. One of the main tasks in the SKB characterization of the HRL rock mass was to predict which of the geological structures will have the greatest rock-mechanical and hydraulic significance. The National Board for Spent Nuclear Fuel (SKN) constructed alternative models in 1992 to verify the SKB model. However, the SKN models were subsequently modified and converted into a hydrogeological model. The Swedish Nuclear Inspectorate (SKI) chose Aespoe as a hypothetical site for storage of nuclear waste in their SITE 94 project. The objective of the project is to assist SKI in their future review of SKB's application for a license to dispose of spent nuclear fuel underground. The agreement of the three models is found to be best where the density of information is greatest. The main difference between the two geological models is related to the inferred effects of block faulting on the rock type distribution. The correlation of moderately to gently inclined zones between the models is relatively poor at depth

 
 
 
 
141

Comparison of the SKI, SKB, and SKN geological and structural models of the Aespoe area  

Energy Technology Data Exchange (ETDEWEB)

Three sets of geological and structural models produced by three different groups are compared. The same set of basic data has been available to each of the groups. The models, all of which are 2 by 2 km by 1 km deep - or smaller, are based entirely on surface-based investigations. The modelled area is centered on the island of Aespoe, where SKB has built the Hard Rock Laboratory (HRL) in plutonic bedrock at a depth of 500 m. SKB (Swedish Nuclear Fuel and Waste Management Co) has recorded the basic data during the period 1986 to 1991, before starting the underground work. One of the main tasks in the SKB characterization of the HRL rock mass was to predict which of the geological structures will have the greatest rock-mechanical and hydraulic significance. The National Board for Spent Nuclear Fuel (SKN) constructed alternative models in 1992 to verify the SKB model. However, the SKN models were subsequently modified and converted into a hydrogeological model. The Swedish Nuclear Inspectorate (SKI) chose Aespoe as a hypothetical site for storage of nuclear waste in their SITE 94 project. The objective of the project is to assist SKI in their future review of SKB`s application for a license to dispose of spent nuclear fuel underground. The agreement of the three models is found to be best where the density of information is greatest. The main difference between the two geological models is related to the inferred effects of block faulting on the rock type distribution. The correlation of moderately to gently inclined zones between the models is relatively poor at depth. 46 refs, 30 figs, 18 tabs.

Tiren, S.A. [Geosigma AB, Uppsala (Sweden)

1996-06-01

142

Geological Geophysical and structural studies in Mina Ratones (Pluton de Albala); Estudios geologico-estructurales y geofisicos en Mina Ratones (Pluton de Albala)  

Energy Technology Data Exchange (ETDEWEB)

Mina Ratones environmental restoration project included petrological, structural,geophysical, hydrogeological and hydrogeochemical studies. The main objective of the geologic-structural and geophysical studies was the Albala granite structural characterization around the Mina Ratones uranium mine. The location of facies, fault zones (faults and dykes) as well as the distribution of some physical properties inside the rock massif was obtained for a granitic black of 900, 500, and 500 m. The geologic-structural and geophysical techniques applied to Mina Ratones provided a multidisciplinary approach for high resolution characterization of rock massif, and the structures potentially containing fluids,able to be applied to the hydrogeological modelling to a particular area. Geological studies included a detailed structural mapping of the area surrounding the mine (1:5,000 scale), the geometric, kinematics, and dynamics analysis of fractures of all scales, the petrology and geochemistry of fault rocks and altered areas surrounding fractures, and the microstructural studies of samples from surface and core lags. The construction of geostatistical models in two and three dimensions had helped to characterize the Mina Ratones rock massif showing the spatial distribution of fault zones, fracture intensity, granite composition heterogeneities, fluid-rock interaction zones, and physical properties. (Author)

Perez-Estaun, A.; Carbonell, R.; Marti, D.; Flecha, I. [Instituto de Ciencias de la Tierra Jaume Almera. Barcelona (Spain); Escuder Viruete, J. [Universidad complutense de Madrid. Madrid (Spain)

2002-07-01

143

An Efficient Method to Recognize Geologic Structures by Analyzing the Pressure Data with Wavelet Transform  

Science.gov (United States)

Uncertainty in prediction of flow performance stems from the uncertainty in model parameters such as conductivity, porosity etc., to a large extent, while the characterization of the model parameters is demanding due to the inherent heterogeneity of geologic structures. Inverse modeling approaches attempt to identify the unknown model structures and corresponding parameters by integrating observation data. Several inverse methods have been proposed in the literature ranging from trial-and-error methods to advanced ensemble Kalman filter assimilation, including those that use multiple point statistics to characterize complex geologic structures. However, these methods are hindered by the huge amount of data accumulated with time, for instance, the pressure data are recorded at very fine time intervals from the very early stage of bore hole drilling to mature production period. Assimilation of such large amount of data can be a computational burden to the inverse methods. The object of this work is to propose a computationally efficient approach to analyze the long observation records in order to recognize the subsurface structures, especially flow connectivity which plays a critical role in transport prediction. Wavelet transform is found to be a powerful technique that transforms data into different components and analyzes each component at corresponding scale. By analyzing the components transformed we relate the characteristics of the heterogeneity to signature in the production/injection records. Combining components at different scales we are able to recognize connectivity between wells, and thereby identify complex structure in aquifers. The method is demonstrated in a synthetic example where CO2 is injected into a deep saline aquifer for sequestration. The method is computationally efficient since it involves no iterative forward simulation or sensitivity matrix computation. Once the important episodes have been identified in the dynamic data, inverse modeling with the reduced data set is supposed to lead to better models for conductivity variations in the aquifer.

Zhou, H.; Srinivasan, S.; Li, L.; Bryant, S. L.

2013-12-01

144

Geological structures from televiewer logs of GT-2, Fenton Hill, New Mexico: Part 1, Feature extraction  

Energy Technology Data Exchange (ETDEWEB)

Patterns in reflected sonic intensity recognized during examination of televiewer logs of basement gneiss at the Hot Dry Rock Site, Fenton Hill, New Mexico, are due to geological fractures and foliations and to incipient breakouts. These features are obscured by artifacts caused by wellbore ellipticity, tool off-centering, and tool oscillations. An interactive method, developed for extraction of the structural features (fractures and foliations), uses human perception as a pattern detector and a chi-square test of harmonic form as a pattern discriminator. From imagery of GT-2, 733 structures were recovered. The acceptance rate of the discriminator was 54%. Despite these positive results, the general conclusion of this study is that intensity-mode imagery from Fenton Hill is not directly invertible for geological information because of the complexity of the televiewer imaging process. Developing a forward model of the intensity-imaging process, or converting to caliper-mode imagery, or doing both, will be necessary for high-fidelity feature extraction from televiewer data.

Burns, K.L.

1987-07-01

145

Dynamic structure and data sets of a GIS database for geological riskanalysis in the Azores volcanic islands  

Directory of Open Access Journals (Sweden)

Full Text Available Geological hazards in the Azores archipelago include earthquakes, volcanic eruptions, degassing phenomena and landslides, being the cause of thousands of deaths and severe damage and loss. To reduce the impact of future events it is necessary to improve the emergency response and reinforce land-use planning, and this has given rise to the development of AZORIS, a GIS database for risk analysis in the Azores. At present this computer-based system comprises nine main dynamic data sets where elemental, monitoring and historical data are grouped in layers of first and second order. The logical structure of the database was conceived in order to facilitate interactivity between data sets and to guarantee the evolution of the system, as determined by the input and the generation of new and more detailed information. Archive organization was designed taking into account regional and local aspects of geological hazard. In order to ensure consistency of the database and the quality of the data within it, an internal process of validation was included.

J. L. Gaspar

2004-01-01

146

VISPECT program evaluation in gamma-ray spectra analysis of neutron-activated geological samples  

International Nuclear Information System (INIS)

A comparative evaluation of gamma-ray analysis software VISPECT in relation to two commercial gamma-ray analysis software packages OMNIGAM (EG and GORTEC) and SAMPO 90 (CANBERRA) was performed. For this evaluation, artificial gamma-ray spectra were created, presenting peaks of different intensities and located at different regions of the spectrum. Multiplet peaks with equal and different intensities, but with different channel separations were also created. Neutron activation analysis of the reference material GS-N (IWG-GIT) was also performed, aiming the evaluation of the program VISPECT in the analysis of a geological sample. (author)

147

Isotopic geology  

International Nuclear Information System (INIS)

Born from the application to geology of nuclear physics techniques, the isotopic geology has revolutionized the Earth's sciences. Beyond the dating of rocks, the tracer techniques have permitted to reconstruct the Earth's dynamics, to measure the temperatures of the past (giving birth to paleoclimatology) and to understand the history of chemical elements thanks to the analysis of meteorites. Today, all domains of Earth sciences appeal more or less to the methods of isotopic geology. In this book, the author explains the principles, methods and recent advances of this science: 1 - isotopes and radioactivity; 2 - principles of isotope dating; 3 - radio-chronological methods; 4 - cosmogenic isotope chronologies; 5 - uncertainties and radio-chronological results; 6 - geochemistry of radiogenic isotopes; 7 - geochemistry of stable isotopes; 8 - isotopic geology and dynamical analysis of reservoirs. (J.S.)

148

Defining geologic Hazards for natural resources management using tree-ring analysis  

Science.gov (United States)

Landslides, avalanches, floods, and other geologic hazards impair natural resources management by jeopardizing public safety, damaging or restricting resource utilization, and necessitating expenditures for corrective measures The negative impact of geologic hazard events can be reduced by tailoring resources management to hazard potential of an area This requires assessment of where and how frequently the events occur National forests and other managed wildlands often lack monitoring or historical records to compute frequency of hazard occurrence Tree-ring analysis, based on internal growth response to external events such as tilting and abrasion, can provide frequency data Two examples of the use of tree-ring analysis to date landslide activity illustrate advantages and limitations of the technique An example from the Fishlake National Forest in central Utah illustrates assessment for planning purposes An example from the Sierra National Forest in east-central California shows assessment applied to project design Many geologic hazards in addition to landslides are suited to tree-ring analysis to establish frequency of occurrence Hazard reduction efforts in natural resources management could be enhanced by careful application of tree-ring analysis ?? 1984 Springer-Verlag New York Inc.

Degraff, J. V.; Agard, S. S.

1984-01-01

149

Evaluation model of commercial geological exploration and mining development project and analysis of some technical problems in commercial negotiation  

International Nuclear Information System (INIS)

A composite evaluation model of commercial geological exploration and mining development project was discussed, this new model consists of polity-economy-technique (PET) synthetic evaluation sub-model and geology-mining-metallurgy (GMM) technique evaluation sub-model. Besides, some key technical problems in commercial negotiation, such as information screening, quoted price and analysis of deadline, were briefly analyzed. (author)

150

Determination of neodymium and gadolinium in geologic samples by neutron activation analysis  

International Nuclear Information System (INIS)

The determination of Nd and Gd present in rocks by neutron activation analysis is aimed at. A separation procedure for the rare earth group of elements is presented. The method is based on the retention of 233Pa, 182Ta and 46Sc by hydrated antimony pentoxide (HAP) in a 6M HClO4 medium. Those radioisotopes are interferences in the gamma-ray spectrum of 153Gd and 147Nd. The reliability of the method was tested by means of the geological standards BCR-1 and G-2 from the U.S. Geological Survey. The limitations of the instrumental neutron activation analysis and the advantages of the chemical separation are discussed for the special case of the Nd and Gd determinations. (Author)

151

Applications of instrumental neutron activation analysis (INAA) for geological samples in AMD for uranium exploration programme  

International Nuclear Information System (INIS)

Full text: Non-destructive Instrumental Neutron Activation Analysis has been used over last three decades in AMD for analysis of geological samples for estimation of Na, K, Ca, Sc, Cr, Fe, Co, Cu, Zn, Ga, As, Br, Zr, Ag, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Tm, Ho, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Au, Th and U. The estimation has been done using various international standards. The irradiation of samples has been done in Cirus/Apsara Reactor in BARC, Mumbai. The measurement of desired gamma emission are carried out by Huge detector. The various geological samples from different parts of India are: 1. granites 2. charnokites 3. Basalts 4. Carbonatites 5. Xenotime 6. Monazite 7. Core samples 8. Black slabs. The efficiency modelling of HPGe detector was done using different sources and mathematical and statistical techniques. (author)

152

Error Analysis of Multi-Source Data for 3D Geological Modeling Using Entropy-based Weighting  

Science.gov (United States)

In each step of geological modeling, errors always have an impact on workflow processes and so have consequences that challenge 3D geological modeling. Methods such as geostatistics, fuzzy set theory and spatial error theory have been used to analyze errors that exist in the raw data behind geological models and these methods assume that a single error distribution exist in all kinds of data. However, different kinds of raw data, such as borehole, user-defined section and geological maps, even within a single kind of data, they may exist different types of positional error distributions. Consequently, analyzing errors of multi-source data for geological modeling remains a vital problem in geological modeling. In this study, we developed a novel approach to quantitatively analyze the distributions of errors in multi-source raw data used for constructing 3D geological structural models. Errors among raw data are usually discussed directly based on the error distributions of points, supposing that the positional error of geological boundaries is caused by spatial measurement rather than uncertainties in the geological attributes. In reality, geological boundaries are given by the distribution of geological attributes of related strata, which are themselves vaguely defined. Therefore, the spatial error in geological boundaries is mainly caused by the uncertainties of geological attributes. Here, we supposed that spatial position is fixed and geological attributes of each point in space vary. According to the spatial relationship between geological attributes and geological boundaries, the spatial error of geological boundaries is transferred into a specific probability of each geological attribute for each point, termed the ';Geological attribute probability'. The key problem in this research is to construct a function for transforming the 3D spatial problem into a 1-D probability distribution problem. We transferred several kinds of spatial error distributions into geological attribute probabilities, allowing different kinds of error distribution of spatial data to be summed directly after the transformation. When building a 3D geological model, several kinds of raw data may cross over one point or line. In this circumstance, an entropy-based weight was given for each kind of data when calculating the final probability. For any point of one data source in space, its geological attribute probability results in an entropy weight value. The larger the value, the smaller the entropy weight. The final geological attribute probability of each spatial point is calculated using a linear entropy-based weighted summation. A color scale is used to illustrate the distribution of geological attribute probability using the MapGIS K9. A concrete example illustrates that geological attribute probability is an effective way of describing multiple error distributions among the raw data used for geological modeling. Acknowledgement: This study is funded by NSFC (41102207) and the Fundamental Research Funds for the Central Universities (121gpy19).

Hou, W.; Yang, L.; Clarke, K.

2013-12-01

153

Geologic mapping of Indonesian rain forest with analysis of multiple SIR-B incidence angles  

Science.gov (United States)

The discrimination and mapping capabilities are to be evaluated for shuttle imaging radar-B (SIR-B) images of geologic features in Indonesia that are covered by equatorial rain forest canopy. The SIR-B backscatter from the rain forest at L-band is to be compared to backscatter acquired by the SEASAT scatterometer system at Ku-band ever corresponding areas. The approach for data acquisition, handling, and analysis and the expected results of the investigation are discussed.

Ford, J. P.; Sabins, F. F., Jr.; Asmoro, P., Jr.

1984-01-01

154

Uranium and thorium analysis in geological samples using SSTD - an application of F/? technique  

International Nuclear Information System (INIS)

The relation connecting concentrations of uranium and thorium atoms in geological samples with the alpha track rate in nuclear emulsions reported by R. Coppens, P. Richard and S. Bashir (1977) is modified for use in the plastic track detector, LR 115 type 2. Gamma ray spectrometric analysis of phosphorite samples from Mussorie syncline establishes the validity of the modified relation and hence will be of use in uranium and thorium estimation using solid state track detectors. 6 refs.. (author)

155

The tunnel project. Drill hole logging and structural geologic studies in the Grualia, the Lunner county  

International Nuclear Information System (INIS)

In connection with the project ''Environmental and community useful tunnels'' the Norwegian Geologic Survey (NGU) has made geologic and geophysical investigations along parts of the tunnel at the Grualia in the Lunner county. The purpose of the geologic studies was to map and investigate weakness zones in the rock foundations. The geophysical studies aimed at testing techniques that was in little use in preliminary studies for tunnel operations. The methods used have been optical inspection of drill holes, measurements of temperature and conductivity in the water and the measuring of the natural gamma radiation in the drill holes. The resistivity in the drill holes is also determined and test pumping with flow measurements is carried out in order to calculate the well water influx capacity. These methods may contribute to information about the rock condition (cracking, water influx). Previously the NGU has made 2D resistivity measurements at the ground in the tunnel in order to map the weakness zones. The results from the measurements in 6 wells show large variations in the rock qualities. The wells are drilled towards indicated weakness zones. Open water conducting cracks and sections with largely cracked rocks are detected in or in the proximity of the tunnel route. The weakness zone between the hornfels and the syenite west of the Langvatnet is largely cracked, has a large water conducting capacity and there are some unstable masses. Further east several open, watele masses. Further east several open, water- conducting cracks are detected in the syenite. Furthest to the east in the route cracked and unstable rocks are found. Several of the holes are blocked by ravines which confirm the poor rock quality. In the particular areas problems are to be expected during the operation with respect to water influx and stability. Methodically the drill hole studies have shown great value for the follow up of the 2D resistivity measurements on the ground. The indicated weakness zones through the 2D have been confirmed and characterised. The testing of the geophysical techniques has so far shown promising results. The 2D resistivity measurements on the ground with subsequent drilling, drill hole logging, pumping and flow measurements would give a good characterisation of the ground where the rock construction is planned. With a good geological foundation (structural mapping) the above techniques would contribute with valuable information concerning what may be expected in front of the hand specimen in tunnel work

156

Crustal structural survey for the state of Minas Gerais, Brazil, utilizing geophysical and geological information  

International Nuclear Information System (INIS)

Gravity, Magnetic (airborne, Magnet and Magsat), heat flow and seismicity available data for the state of Minas Gerais and adjacent regions is here analyzed, discussed and integrated with geologic information. The Late Archean crustal structure is defined as blocks of granite-greenstone separated by belts of high-grade terrains. The belts in eastern and southern Minas Gerais represent the lower parts of the Vitoria, Sao Paulo and Parana Blocks, which were up thrusted over the Brasilia Block through low-angle ductile simple shear Zones. That regional structure is cut and somewhat displaced by NW, ENE, NE and Ns fault sets. These faults are mostly related to the Transamazonian Event, and their geological expression appears to be as high-angle ductile simple shear zones. The development of the Middle/upper proterozoic folded sequences, the incidence of the Brasiliano/Uruacuano thermo tectonic events and the geometry of the Sao Francisco Craton were highly influenced by the preexistent weakness zones. The high-grade terrains, the borders of the Brasilia Block and the Transamazonian lineaments have been preferentially affected. The tectono-magmatic manifestations of the Wealdenian Reactivation, related to the opening of the Atlantic Ocean, occurred mostly among the uplifted zones (Alto Paranaiba Uplift) that developed partially until the rift stage (Mantiqueira Uplift). These processes clearly reveal the influence of the old structures of the state of Minas Gerais. The Manures of the state of Minas Gerais. The Mantiqueira Uplift presents a more accentuated seismic activity and thermal flow regime than the neighboring regions, so corresponding to the present less stable area of Minas Gerais. (DJM)

157

Analysis of geological condition of uranium mineralization in the Xiangshan northern uranium orefield in central region of Jiangxi Province  

International Nuclear Information System (INIS)

According to the basic conditions of 'source, guide, transportation, storage' for uranium mineralization in strata and different types of geological structure, departure from the condition, the coupling effect of stratigraphy, lithology and structure are studied in the process of uranium mineralization in northern Xiangshan volcanic basin. Studies show that the northern ore field are of good metallogenic geological conditions and the uranium rich ancient land mass and uranium rich magma generated by the melting of deep metamorphic rocks. The main geologic events are volcanic eruptions, accompanied by repeated subvolcanic magma intrusion and strong faults and nappe tectonics which result in volcanic collapse and volcanic ring structures. These ore-forming geological condition control the structural frame for the formation of main uranium deposit type-subvolcanic rocks in northern Xiangshan ore field. (authors)

158

Dynamic simulations of geologic materials using combined FEM/DEM/SPH analysis  

Energy Technology Data Exchange (ETDEWEB)

An overview of the Lawrence Discrete Element Code (LDEC) is presented, and results from a study investigating the effect of explosive and impact loading on geologic materials using the Livermore Distinct Element Code (LDEC) are detailed. LDEC was initially developed to simulate tunnels and other structures in jointed rock masses using large numbers of polyhedral blocks. Many geophysical applications, such as projectile penetration into rock, concrete targets, and boulder fields, require a combination of continuum and discrete methods in order to predict the formation and interaction of the fragments produced. In an effort to model this class of problems, LDEC now includes implementations of Cosserat point theory and cohesive elements. This approach directly simulates the transition from continuum to discontinuum behavior, thereby allowing for dynamic fracture within a combined finite element/discrete element framework. In addition, there are many application involving geologic materials where fluid-structure interaction is important. To facilitate solution of this class of problems a Smooth Particle Hydrodynamics (SPH) capability has been incorporated into LDEC to simulate fully coupled systems involving geologic materials and a saturating fluid. We will present results from a study of a broad range of geomechanical problems that exercise the various components of LDEC in isolation and in tandem.

Morris, J P; Johnson, S M

2008-03-26

159

Dynamic analysis of multiperiodic structures  

International Nuclear Information System (INIS)

A multiperiodic structure consists of repetition of periodic elements for example, periodic skin stringer structure used in aircrafts fuselage. The analysis of simple periodic structure is extended for compound periodic structure in this paper, using wave analysis approach. The characteristic waves are propagated along the structure and these are superimposed on each other. The propagation and attenuation bands are separated from each other and are discussed. (author)

160

Geology of the ?oka structure in northern Banat (Central Paratethys, Serbia)  

Science.gov (United States)

The ?oka structure is a fault-bounded anticline in northern Banat, in the southern part of the Neogene Pannonian Basin. The structure and its vicinity were explored by 24 wells. In addition to well logs, paleontological, sedimentological and petrological analyses of cores and 27 seismic sections with different parameters of acquisition and processing were used for geological investigation of the area. The E-SE dipping pre-Neogene basement consists of Lower Triassic clastics and, in the NW part of the study area, Paleozoic greenschists. Thin Middle Miocene (Badenian) sediments unconformably overlie the basement and pinch out towards the elevated NW part of the study area. They are also missing in some wells on the apex of the ?oka structure, probably due to erosion. Badenian sediments were deposited in a shallow marine environment. The late Middle Miocene (Sarmatian) strata are missing and the Badenian is directly overlain by Upper Miocene (Pannonian) sediments. The latter also pinch out towards the NW but in contrast to Badenian sediments, they are present in all boreholes on the ?oka structure. Pannonian deposition took place in a caspibrackish environment of Lake Pannon, with predominance of marls and fine-grained clastics. Pannonian sediments are conformably overlain by latest Miocene (Pontian) and Pleistocene lacustrine, alluvial and terrestrial sediments.

Radivojevi?, Dejan; Rundi?, Ljupko; Kneževi?, Slobodan

2010-08-01

 
 
 
 
161

Geologic structure of the northern New Caledonia ridge, as inferred from magnetic and gravity anomalies  

Science.gov (United States)

Bathymetric, gravity, and magnetic data collected in the southwest Pacific Ocean over the northern New Caledonia ridge show that the main geological units known from the island of New Caledonia extend northward from this island, beneath the Grand Lagon Nord, the Grand Passage, and the d'Entrecasteaux reefs. These data support the model of tectonic evolution of the New Caledonia region proposed by Kroenke (1984). Differences in structure, geophysical signatures and morphology evident between areas north and those south of the Grand Passage, together with the nearness of the Le Noroit massif west of the Grand Passage, suggest that contemporaneously with Eocene to early Oligocene subduction along the western New Caledonia margin, an arc-ridge collision may have occurred near the northern termination of this subduction zone. -from Authors

Collot, J. Y.; Rigolot, P.; Missegue, F.

1988-01-01

162

Yasny lode-placer cluster: Geological and structural features and gold potential  

Science.gov (United States)

The geological and structural features and gold potential of the Yasny lode-placer cluster in Amur province have been investigated. The lode-placer cluster is an intrusive domal uplift elongated in the nearmeridional direction and surrounded by Neogene loose sediments. The cluster comprises placers that yielded 15 t gold mined from there and small occurrences of gold-quartz and gold-base-metal lodes. Association of native gold with cinnabar in the Yasny Creek placer allows us to forecast a new source of gold-mercury mineralization in the basin of this creek, which could be compared with the Kyuchyus deposit in Yakutia. Gold nuggets 79 kg in total weight were mined from Gar-2 River placer. They are comparable in weight and association with quartz to the world's largest Holtermann Plate nugget from Australia. Gold-quartz lodes have been forecasted in the basin of the Gar-2 Creek.

Mel'nikov, A. V.; Stepanov, V. A.

2014-03-01

163

Integration of reservoir geology, structural geology, and production history for Viking gas production from Ricinus/Bearberry area of the Rocky Mountain Triangle Zone  

Energy Technology Data Exchange (ETDEWEB)

The depositional history and structural geometry of the Ricinus/Bearberry Viking gas field was described. The field is located in the foothills of the Rocky Mountain Fold and Thrust Belt about 100 km northwest of Calgary, Alberta. The first producible sweet gas well in the area was drilled in 1972. The field is characterised by a series of northeast-verging thrust faults which ramp off of a basal detachment in the mixed continental section of the Mannville Group which underlies the Viking Formation. It has been assumed by the petroleum industry that targeting the front of major structural features is critical for improved productivity. Several production parameters could be cross-correlated with reservoir and structural geological parameters to try to clarify linkages such as gas rate, recoverable gas, drainage area, and decline performance. 2 figs.

Halwas, D.; Cutten, F.; Whyte, R.; Gapp, J. [Petro-Canada Oil and Gas, Calgary, AB (Canada)

1999-11-01

164

Study on systemizing the technology on the investigation and analysis of deep underground geological environment, 2003  

International Nuclear Information System (INIS)

The following study was done in this year with the aim of systemizing the technology on the investigation and analysis to grasp deep underground geological environment in relation to the radioactive waste disposal. (1) The study to extract the research and development (R and D) subjects turned to the practical investigation and analysis of deep underground geological environment. (2) The study on the advanced technical basis of the investigation and analysis of deep underground geological environment. It continued in the former year and got the following results. Concerning (1), the concrete investigation, measurement and numerical/chemical analyses were enforced about the following item and extracted some subjects with the viewpoint of radioactive waste disposal. 1. The subjects extracted with the viewpoint of the repository design and engineering technology. The evaluation technique of the excavation disturbed zone (EDZ) by acoustic emission (AE) or micro seismicity measurement. Fracture sealing technique such as vibration grouting toward low permeable rock mass. 2. The subject extracted with the viewpoint of the safety assessment. Precipitation of the metal hydroxide ((non-crystallized) through migration process in rock mass and change to the crystallized oxide. 3. The subjects extracted with the viewpoint of the geological environment. Fracture distribution characteristics around the fault, it can think to meet in the underground facilities and the prediction of lrground facilities and the prediction of long term activities of the fault. Natural sealing process by the secondary filling materials (iron oxide and carbonate etc.) in the fracture of rock mass and that influence which may be given to the long-term migration and release of nuclides. The advanced research subjects among the each field of 1, 2, 3 were also discussed. Concerning (2), the evaluation of the results and a way to the practical use were discussed on the R and D activities of the following item. 1. The introduction of the genetic algorithms to the hydraulic analysis of fractured rock mass. 2. The applicable evaluation of the tracer test and the numerical analysis tool to investigate the ground water path in fractured rock mass. 3. Ground water temperature and pore pressure measuring system which optical fiber was used for. 4. Modeling on the migration of the material and the regional ground water circulation. 5. Grasping of the ground water flow mechanism by stable isotope. The R and D activities of the committee member concerning (2) are related to the fundamental and elemental technology. It was also discussed if these results could be taken in the practical investigation program for characterization of the geological environment and engineering technology in the Tono Geoscience Center, the Japan Nuclear Cycle Development Institute (JNC). (author)

165

Cassini/VIMS Data Analysis of Potentially Geologically Varying Regions on Titan  

Science.gov (United States)

We present a study of Titan's geology with a view to enhance our current understanding of some particular regions on the satellite's surface, which may be varying in brightness and/or in color etc. We apply here a statistical method, the Principal Component Analysis (PCA) [1] and a radiative transfer code (RT) [1,2] on three such potentially "active" regions: Tui Regio, Hotei Regio, and Sotra Facula, within which we isolate specific regions of distinct and diverse chemical composition with PCA. Then, with our follow-up RT method, we retrieve the surface albedo of these specific isolated regions and of the surrounding terrains exhibiting different spectral responses. We thus evaluate the atmospheric contribution and can constrain the real surface alterations, by comparing the spectra of these regions. We search for the temporal surface variations of Hotei Regio (as reported by Nelson et al. 2009 [3]), with our RT code and the same data from 2004-2006, and do not find any significant surface albedo variations over time. We then superimposed this area's Cassini Visual and Infrared Mapping Spectrometer (VIMS) and RADAR data in order to 'view' the morphological potential. We find that 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 [4] observed in these areas do not rule out past and/or ongoing cryovolcanic processes as a possible interpretation. [1] Solomonidou, A., et al.: In preparation. [2] Hirtzig, M. et al.: In preparation. [3] Nelson, R. et al.: Icarus 199, 429-441, 2009. [4] Solomonidou, A et al.: PSS, accepted, 2012.

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

2012-10-01

166

A fluid pressure and deformation analysis for geological sequestration of carbon dioxide  

Energy Technology Data Exchange (ETDEWEB)

We present a hydro-mechanical model and deformation analysis for geological sequestration of carbon dioxide. The model considers the poroelastic effects by taking into account the two-way coupling between the geomechanical response and the fluid flow process in greater detail. In order for analytical solutions, the simplified hydro-mechanical model includes the geomechanical part that relies on the theory of linear elasticity, while the fluid flow is based on the Darcy’s law. The model was derived through coupling the two parts using the standard linear poroelasticity theory. Analytical solutions for fluid pressure field were obtained for a typical geological sequestration scenario and the solutions for ground deformation were obtained using the method of Green’s function. Solutions predict the temporal and spatial variation of fluid pressure, the effect of permeability and elastic modulus on the fluid pressure, the ground surface uplift, and the radial deformation during the entire injection period.

Xu, Zhijie; Fang, Yilin; Scheibe, Timothy D.; Bonneville, Alain

2012-06-07

167

The analysis of geological samples using NAA methods in RSG-GAS  

International Nuclear Information System (INIS)

Because of irradiation facilities usage and development of NAA method in P2TRR, the geological samples was analyzed by NAA method. The aim of this research is to know the elements contain in geological samples. The samples were irradiated in the RSG-GAS's rabbit system. Samples pasca irradiation were measured by gamma spectrometer. The results of analysis showed that the stone samples contained different elements : Ce, Cr, Co, Fe, La, Lu, Na, Np, Pd, and Sm. The sand samples contained: Bi, Cd, Cs, Co, Fe, Eu, K, Pd, La, Lu, Na, Sc, Sm, Th, and Yb elements. There was a variation in elements concentration between 1.34 ppm Cr (lowest) and 179.06 ppm Sr (highest)

168

Locating and quantifying geological uncertainty in three-dimensional models: Analysis of the Gippsland Basin, southeastern Australia  

Science.gov (United States)

Geological three-dimensional (3D) models are constructed to reliably represent a given geological target. The reliability of a model is heavily dependent on the input data and is sensitive to uncertainty. This study examines the uncertainty introduced by geological orientation data by producing a suite of implicit 3d models generated from orientation measurements subjected to uncertainty simulations. The resulting uncertainty associated with different regions of the geological model can be located, quantified and visualised, providing a useful method to assess model reliability. The method is tested on a natural geological setting in the Gippsland Basin, southeastern Australia, where modelled geological surfaces are assessed for uncertainty. The concept of stratigraphic variability is introduced and analysis of the input data is performed using two uncertainty visualisation methods. Uncertainty visualisation through stratigraphic variability is designed to convey the complex concept of 3D model uncertainty to the geoscientist in an effective manner. Uncertainty analysis determined that additional seismic information provides an effective means of constraining modelled geology and reducing uncertainty in regions proximal to the seismic sections. Improvements to the reliability of high uncertainty regions achieved using information gathered from uncertainty visualisations are quantified in a comparative case study. Uncertainty in specific model locations is identified and attributed to possible disagreements between seismic and isopach data. Further improvements to and additional sources of data for the model are proposed based on this information. Finally, a method of introducing stratigraphic variability values as geological constraints for geophysical inversion is presented.

Lindsay, Mark D.; Aillères, Laurent; Jessell, Mark W.; de Kemp, Eric A.; Betts, Peter G.

2012-06-01

169

Scientific Journals as Fossil Traces of Sweeping Change in the Structure and Practice of Modern Geology  

Directory of Open Access Journals (Sweden)

Full Text Available In our attempts to track changes in geological practice over time and to isolate the source of these changes, we have found that they are largely connected with the germination of new geologic subdisciplines. We use keyword and title data from articles in 68 geology journals to track the changes in influence of each subdiscipline on geology over all. Geological research has shifted emphasis over the study period, moving away from economic geology and petroleum geology, towards physics- and chemistry-based topics. The Apollo lunar landings had as much influence on the topics and practice of geological research as the much-cited plate-tectonics revolution. These results reflect the barely-tangible effects of the changes in vocabulary and habit of thought that have pervaded the substance of geology. Geological literature has increased in volume and specialization, resulting in a highly fragmentary literature. However, we infer that "big science," characterized by large amounts of funding, collaboration, and large logistical investments, makes use of this specialization and turns "twigging" into a phenomenon that enhances, rather than inhibits, the enterprise of research.

H. L. Vacher

2008-01-01

170

Analysis by neutronic activation of samples of a geologic formation of Cuba  

International Nuclear Information System (INIS)

The analysis by neutronic activation (AAN) is an analytical non destructive technique of high accuracy and sensibility. These advantages are very utilized in the determination of geological multielemental samples. In the job 22 elements are determined in 9 geological samples pertaining to the complex of dams of acid composition that includes the graphitic micaceous schist and the quartzites of the Canada Formation, developed fundamentally in the fasteners of the anticlinal Victoria (Yac. of Wolframio Lela, Island of the Youth, Cuba) The results obtained are of great importance for the evaluation of the potentiality of these rocks as fountains or of uranium adjusting and for the geologic prognostic of the region in study. The irradiation of the samples was carried out during three campaigns, in two occasions (October 1992 and November 1994) in the reactor of investigations of the ININ of Mexico, with a flow of thermic neutrons of 10a the 13 n.s-1 cm-2 and in an occasion in the nuclear reactor of the CAB (september 1994), with a flow of thermic neutrons of 6x 10 to the 12 n.s-1. The results were processed with the program ACTAM in the CEADEN. (S. Grainger)

171

Thermo-mechanical sensitivity analysis of repository design parameters using Korean geological conditions  

International Nuclear Information System (INIS)

Extensive sensitivity analysis had been carried out for the seven design parameters, which can influence on the thermal-mechanical coupling behavior because of the stress in deep underground as well as the heat from the high-level radioactive waste. In this study, the three-dimensional commercial code, FLAC3D, was used for analyzing the sensitivity of the design parameters, which are related to disposal tunnel and deposition hole, on the temperature, stress, and displacement. The geological data measured at the two drilling sites, Yusung and Kosung, were used in the modelings. From the modelings, it was possible to investigate the thermal-mechanical coupling behavior of the deep underground repository under Korean geological conditions. Fractional factorial design was utilized for effective experimental design for the sensitivity analysis. Different techniques of sensitivity analysis were applied for the modeling results. From the analysis, it was possible to conclude that the deposition hole spacing is the most important parameter on the thermal-mechanical coupling behavior

172

Yucca Mountain thermal response: An evaluation of the effects of modeled geologic structure and thermal property descriptions  

International Nuclear Information System (INIS)

To assess the influence of mountain-scale thermal property model variations on predicted host-rock thermal response, a series of heat conduction calculations were run using a representative two-dimensional cross section of Yucca Mountain. The effects of modeled geologic structure were evaluated through comparisons of results from a single-material, homogeneous model with those from a uniformly layered model, a discontinuous sloping-layered model, and a geo-statistical realization of thermal properties. Comparisons indicate that assumed geologic structure can result in up to a 24 degrees C difference in predicted temperature response. Further, thermal simulations of the method used to analyze geostatistical realizations of thermal properties shows promise as an efficient means of capturing geologic structure without the complexities of intricate finite element meshing. The functional representation of two thermal property models were also investigated. The first examines the effect of using a weighting scheme to define properties for a single, homogenous material model. The second investigates the impact of thermal property temperature dependence on predicted response. As with the investigation of geologic structure, noticeable differences in predicted temperatures (up to 29 degrees C) were found to result

173

Structural geology of the Columbia Plateau and environs as related to the waste isolation safety assessment program  

International Nuclear Information System (INIS)

This report provides information on the structural geology of the Columbia Plateau in regard to selecting a site for radioactive waste disposal. This report describes the folding and faulting that has taken place during the past several million years, thus providing background for the general stress conditions of the area and giving clues to the mechanism of deformation

174

Considerations on diversion analysis and the design of a safeguards approach. A case study of a geological repository for final disposal of spent fuel  

International Nuclear Information System (INIS)

Direct disposal of spent fuel has developed as an important option for the nuclear fuel cycle. The direct final disposal of spent nuclear fuel in a geological repository, as it is planned in Germany, makes new demands on international nuclear materials safeguards and requires the development of a new safeguards system, since no model procedures exist as yet. The development of an effective safeguards system and evaluation of alternative safeguards approaches calls for a comprehensive analysis of possible diversion paths together with an assessment as to what extent the relevant paths can be covered by safeguards measures. Since there are no prescribed and formalized procedures as to how to conduct the analysis, we try to apply the logical framework provided by material accountancy also as a basic structure for the diversion path analysis. This procedure can help to identify clearly the crucial points and novel safeguards issues raised by a geological disposal facility. (author). 1 fig

175

Ore lead isotopic composition as defined by geological structure: the central part of the North-East Asia territory  

International Nuclear Information System (INIS)

By means of mass-spectroscopy one investigated into isotopic composition of lead of sulfide ore galenites from the deposits in the North-East of Russia to determine correlation between isotopic characteristics of ore lead, on the one hand, geological structure and history of this region, on the other hand. On the basis of the obtained experimental data one calculated a model 207Pb-206Pb-age of ore deposits in that region. It is shown that within the limits of Verkhoyano-Chukot folding territory there are three lead-isotopic provinces differing in age of deposits, in geological and physicochemical conditions of orebody formation

176

Crystal structure analysis  

International Nuclear Information System (INIS)

The paper deals with the following: 1) Definition of a crystal 2) Basic elements of crystal structure determination 3) Fourier representation of the electron density of a crystal and reciprocal lattice 4) Diffraction by a crystal 5) The process of determing a crystal's structure 5.1.) Determination of lattice constants 5.2.) Determination of atomic layers 6) Crystal lattice symmetries. (orig.)

177

Experimental performance evaluation of a compton suppression system by an analysis of geological reference materials  

Energy Technology Data Exchange (ETDEWEB)

Compton scattering is one of major sources inducing a high background when a gamma ray spectrum is acquired from a radioactive sample. The high background spectrum deteriorates the detection sensitivity for an analysis of the nuclide of interest. To improve the detection sensitivity by the reduction of the spectrum background, a Compton suppression system (CSS) applying an anti coincidence mode was developed and has been used for a neutron activation analysis. A Compton suppression system (CSS) was implemented for an instrumental neutron activation analysis (INAA) at an NAA laboratory of the Korea Atomic Energy Research Institute (KAERI) in 2009. The CSS consists of a high purity Ge (HPGe) detector and bismuth germinate (BGO) with electronic modules. An evaluation of the performance of the CSS was carried out based on the measurement of the gamma ray emitting source and the detectable nuclides created thorough neutron activation of biological reference materials. This study was executed to evaluate the performance of the CSS for geological standard reference materials (SRMs). Four geological SRMs produced by the National Institute of Standards and Technology (NIST) in the USA were selected and irradiated using an NAA 1 irradiation hole at HANARO. Gamma ray spectra with normal mode and anti coincidence mode were acquired at the same time, and advantage factors of CSS for each nuclide detected were calculated on the basis of the signal to noise ratio.

Moon, J. H.; Sun, G. M.; Kim, S. H.; Chung, Y. S. [KAERI, Daejeon (Korea, Republic of)

2012-10-15

178

Applicability of direct total reflection X-ray fluorescence spectrometry for multielement analysis of geological and environmental objects  

Science.gov (United States)

The research aim is to demonstrate our experience in the applicability of TXRF analysis of various geological and environmental objects using minimal sample treatment. The study was focused on the evaluation of different factors affecting the TXRF results obtained for solid and liquid samples such as rock, mineral, ore, and natural water. Powdered geological samples were prepared as suspensions. Natural water samples were analyzed directly or after dilution. Testing various experimental parameters, e.g. sample amount, type of dispersant, and others was performed. For chosen conditions of the sample preparation procedure analytical figures of merit were estimated. Presented analytical results display the possibilities of TXRF applications in geological and environmental fields.

Cherkashina, T. Yu.; Panteeva, S. V.; Pashkova, G. V.

2014-09-01

179

THE SIGNIFICANCE OF STRUCTURAL AND GEOLOGICAL RELATIONSHIP ASSESSMENT IN THE CONSTRUCTION OF THE OMBLA UNDERGROUND HYDROELECTRIC POWER PLANT  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The construction design of the underground hydroelectric plant Ombla required geological and structural investigations to he carried out. Due to past earthquakes in the area permanent tectonic movements were inferred. Therefore, in the wider and adjacent surroundings of the Ombla spring it was necessary to analyze the structural fabric and the geodynamic characteristics of the area. The most active zone encountered is the front part of a thrust fault belonging to the Dinaricum regional struct...

Eduard Prelogovi?; Renato Buljan

1997-01-01

180

Estimating Sliding Velocity of a Pleistocene Ice Sheet From Plowing Structures in the Geologic Record  

Science.gov (United States)

As an ice sheet slides over a sediment bed, some clasts partly embedded in the glacier sole plow through the bed surface. The size distribution of such clasts, if it can be characterized from structures in the geologic record, can be used to estimate the sliding velocity of a past ice sheet. By combining a theory of glacier sliding with a geotechnical theory of cone penetration, sliding velocity can be calculated in terms of clast-size parameters, a fluidity parameter for ice, and the thermodynamic properties of ice and clasts. If frictional properties of the bed are measured, the effective normal stress on the bed and bed shear strength during glaciation can also be calculated. We used this approach to estimate the sliding velocity of an Illinoian ice sheet that left plowing structures in cemented outwash near Peoria, Illinois. Fluidity parameters for normal and basal temperate ice yielded sliding velocities of 140-168 m/yr and 60-72 m/yr, respectively. These are overestimates if solutes impeded regelation of ice past clasts or if friction between debris-laden ice and clasts retarded slip. Preconsolidation stresses determined in laboratory tests on silt from the bed agree with effective normal stresses calculated using clast-size parameters. The high shear strength of the bed (>145 kPa) and primary structures preserved within it indicate that additional movement due to pervasive shear of the bed was unlikely. Application of this method elsewhere where basal tills overly outwash would provide basal-velocity data that are otherwise unavailable for testing and tuning of ice-sheet models; we know of no other method for estimating sliding velocity from glacial sediments.

Iverson, N. R.; Hooyer, T. S.

2004-05-01

 
 
 
 
181

Estimating the sliding velocity of a Pleistocene ice sheet from plowing structures in the geologic record  

Science.gov (United States)

As an ice sheet slides over its sediment bed, some clasts partly embedded in the glacier sole plow through the bed surface. The size distribution of such clasts, if it can be characterized from structures in the geologic record, can be used to estimate the sliding velocity of a past ice sheet. By combining a theory of glacier sliding with a geotechnical theory of cone penetration, sliding velocity can be calculated in terms of clast-size parameters, a fluidity parameter for ice, and the thermodynamic properties of ice and clasts. If frictional properties of the bed are measured, the effective normal stress on the bed and bed shear strength during glaciation can also be calculated. We used this approach to estimate the sliding velocity of an Illinoian ice sheet that left plowing structures in cemented outwash near Peoria, Illinois. Fluidity parameters for normal and basal temperate ice yielded sliding velocities of 140-168 m yr-1 and 60-72 m yr-1, respectively. These are overestimates if solutes impeded regelation of ice past clasts or if friction between debris-laden ice and clasts retarded slip. Preconsolidation stresses determined in laboratory tests on silt from the bed agree with effective normal stresses calculated using clast-size parameters. The high shear strength of the bed (>145 kPa) and primary structures preserved within it indicate that additional movement due to pervasive shear of the bed was unlikely. Application of this method elsewhere would provide basal velocity data that are otherwise unavailable for testing and tuning of ice sheet models.

Iverson, Neal R.; Hooyer, Thomas S.

2004-12-01

182

Simulations of Fracture and Fragmentation of Geologic Materials using Combined FEM/DEM Analysis  

Energy Technology Data Exchange (ETDEWEB)

Results are presented from a study investigating the effect of explosive and impact loading on geological media using the Livermore Distinct Element Code (LDEC). LDEC was initially developed to simulate tunnels and other structures in jointed rock masses with large numbers of intact polyhedral blocks. However, underground structures in jointed rock subjected to explosive loading can fail due to both rock motion along preexisting interfaces and fracture of the intact rock mass itself. Many geophysical applications, such as projectile penetration into rock, concrete targets, and boulder fields, require a combination of continuum and discrete methods in order to predict the formation and interaction of the fragments produced. In an effort to model these types of problems, we have implemented Cosserat point theory and cohesive element formulations into the current version of LDEC, thereby allowing for dynamic fracture and combined finite element/discrete element simulations. Results of a large-scale LLNL simulation of an explosive shock wave impacting an elaborate underground facility are also discussed. It is confirmed that persistent joints lead to an underestimation of the impact energy needed to fill the tunnel systems with rubble. Non-persistent joint patterns, which are typical of real geologies, inhibit shear within the surrounding rock mass and significantly increase the load required to collapse a tunnel.

Morris, J P; Rubin, M B; Block, G I; Bonner, M P

2005-05-26

183

Study on systemizing the technology on the investigation and analysis of deep underground geological environment, 2005  

International Nuclear Information System (INIS)

The following study was done in this year with the aim of systemizing the technology on the investigation and analysis to grasp deep underground geological environment in relation to the radioactive waste disposal. (1) The study to extract the research and development (R and D) subjects turned to the practical investigation and analysis of deep underground geological environment. (2) The study on the advanced technical basis of the investigation and analysis of deep underground geological environment. It continued in the former year and got the following results. Concerning (1), the concrete investigation, measurement, numerical analyses and chemical analyses were enforced about the following item and extracted some subjects with the viewpoint of radioactive waste disposal. More over, the way to make the co-operative program among each field of the following 1), 2), and 3) was discussed. 1) The subjects extracted with the viewpoint of the repository design and engineering technology: The evaluation technique of the excavation disturbed zone (EDZ) of hard fractured rock using acoustic emission (AE) or micro seismicity measurement and so on. The evaluation was enlarged to the soft sedimentary rock in this year. The fracture sealing technique such as vibration grouting toward low permeable rock mass. 2) The subject extracted with the viewpoint of the safety assessment: The precipitation of the metal hydroxide (non-crystallized) through migration process in rock mass and hrough migration process in rock mass and change to the crystallized oxide. The examination of Fe-hydroxide was the target study in this year. The evaluation of corrosion affected by high-Eh ground water and/or oxidized substances. 3) The subjects extracted with the viewpoint of the geological environment: The fracture distribution characteristics around the fault that is thought to meet in the underground facilities and the prediction of long term activities of the fault. Natural sealing process by the secondary filling materials (iron oxide and carbonate and so on) in the fracture of rock mass, and that influence which may be given to the long-term migration and release of nuclides. (author)

184

Information on subsoil geological structure in the city of Catania (Eastern Sicily from microtremor measurements  

Directory of Open Access Journals (Sweden)

Full Text Available Nakamura?s technique, or the H/V spectral ratio method, has been applied to microtremor measurements carried out in the urban area of Catania (Eastern Sicily to obtain information on the geological structure of some sites,and to make a hypothesis on their seismic response. In general, sites located on soft soils or anthropic debris fillings have shown greater amplification at high frequencies (above 1 Hz. However, a strong lateral variation was observed in the frequency band, thus a denser grid of measurement points is necessary for a precise mapping of the resonant frequencies. In the low frequency range, between 0.1 and 1 Hz, a common peak around 0.2 Hz was observed. The fundamental resonant frequency inferred from the main peak in the H/V spectrum has been used to calculate the depth of the interface between the clays and the main reflector on the basis of the shear-wave velocity: it has been estimated as about 700 m.

M. R. Gallipoli

2001-06-01

185

Geological structure of the offshore Sumatra forearc region estimated from high-resolution MCS reflection survey  

Science.gov (United States)

To investigate detailed fault distributions and shallow geological structure offshore northwestern Sumatra, we obtained high-resolution Multi-Channel Seismic (MCS) reflection data around the Sunda Trench, trench slope, and forearc high regions offshore northwestern Sumatra. In general, trench-parallel anticlinal ridges are distributed from trench slope region to forearc high region. Two kinds of different vergence systems are characterized in the Sumatra forearc region; landward vergence is dominant in the lower trench slope region, and seaward vergence is dominant in the forearc high region. Moreover, piggyback or slope basins are recognized between anticlinal ridges. Deformation in the uppermost part of these basins, that is referred to ‘recent’ deformation in this paper, can be identified not only along major thrusts but also between major thrusts and the lower trench slope, suggesting these are related to recently active faulting. Several but the largest number of such deformation are distributed along a major thrust located in the middle of the forearc high region, whereas few are done along other major thrusts.

Misawa, Ayanori; Hirata, Kenji; Seeber, Leonard; Arai, Kohsaku; Nakamura, Yasuyuki; Rahardiawan, Riza; Udrekh; Fujiwara, Toshiya; Kinoshita, Masataka; Baba, Hisatoshi; Kameo, Katsura; Adachi, Keita; Sarukawa, Hiroshi; Tokuyama, Hidekazu; Permana, Haryadi; Djajadihardja, Yusuf S.; Ashi, Juichiro

2014-01-01

186

Evidence For The Strong Influence Of Structural Geology On Shallow Microseismicity  

Science.gov (United States)

Induced seismicity is usually associated with individual pre-existing faults whose nature is generally unknown. The high uncertainties in the locations of the earthquakes (50 m in one study and generally >100 m) combined with the absence of geological observations, permits only un-validated assumptions about the mechanism and the structures on which shallow seismicity occurs. More detailed knowledge on the physics of earthquakes is limited to events with magnitude Mw > 4 at depths usually >100km so that location errors do not jeopardise the reliability of the results. This lack of accurate locations has led most studies to a common assumption; that the seismicity is concentrated on a single slip surface associated with each individual fault segment. This assumption has significant implications for industries such as geothermal energy exploitation, deep well injection of waste liquids and underground nuclear waste disposal, where prediction of hydraulic and mechanical property evolution is required for large rock masses, over long time-scales. For this study we use a high quality seismic monitoring record obtained using 3-component digital seismometers. The monitoring covered a 3-yr period, from 1994 to 1997, took place at the Acu water reservoir (NE Brazil) and is associated with a strike-slip fault trending at approximately 47 deg. We achieve location accuracies better than 20m for 185 shallow ( 120000 m2, some of which are adjacent and co-planar. We conducted several geological field campaigns around the study area. Observations from a nearby exposed sub-parallel fault show it to be a ‘mature’ fault with a well-defined fault core that contained no open fractures and an associated damage zone >100m in width. Sets of open shear fractures associated with the damage zone correspond well to the shear planes estimated from the seismic data. Our results reveal that seismicity is not occurring on the main fault but is distributed over a wide (~ 1.5km long and 500m wide) associated damage zone. The damage zone is characterised by micro-seismically active shear fractures. These micro-seismic events have ‘rupture patches’ with areas of 5000-15000m2 and are triggered by very small changes in groundwater pressure. This will result in temporal changes to fracture connectivity and flow within individual shear fractures. Our findings have significant implications for permeability estimation at shallow depths over long time scales.

Pytharouli, S.; Kirkpatrick, J. D.; Lunn, R. J.; Do Nascimento, A.; Shipton, Z. K.

2009-12-01

187

Analysis of the Spent Fuel Cooling Time for a Deep Geological Disposal  

International Nuclear Information System (INIS)

The purpose of the HLW deep geological disposal is to isolate and to delay the radioactive material release to human beings and the environment for a long time so that the toxicity does not affect to the environment. The main requirements for the HLW repository design is to keep the buffer temperature below in order to maintain its integrity. So the cooling time of spent fuels discharged from the nuclear power plant is the key consideration factors for efficiency and economic feasibility of the repository. The disposal tunnel/disposal hole spacing, the disposal area and thermal capacity required for the deep geological repository layout which satisfies the temperature requirement of the disposal system is analyzed to set the optimized spent fuels cooling time. To do this, based on the reference disposal concept, thermal stability analyses of the disposal system have been performed and the derived results have been compared by setting the spent fuels cooling time and the disposal tunnel/disposal hole spacing in various ways. From these results, desirable spent fuels cooling time in view of disposal area is derived. The results shows that the time reaching the maximum temperature within the design limit of the temperature in the disposal site is likely shortened as the cooling time of spent fuels becomes short. Also it seems that the temperature-rising and-dropping patterns in the disposal site are of smoothly varying form as the cooling time of spent fuels becomes longe cooling time of spent fuels becomes long. In addition, it is revealed that a desirable cooling time of spent fuels is approximately 40-50 years when spent fuels are supposedly disposed in the deep geological disposal site with its structural scale under consideration in this study.

188

Formation and evolution of the midlands of Venus: Geological features and structures, stratigraphic relationships and geologic history of the Fredegonde area (V-57)  

Science.gov (United States)

The topographic midlands on Venus comprise about 80% of the surface and an understanding of their mode of formation is essential to unraveling the geologic and geodynamic history of the planet. We explore this question by undertaking a comprehensive geological mapping of the Fredegonde Quadrangle (V-57, 50-75°S, 60-120°E, 1:5M scale) that represents the transition zone from the midlands to the lowlands at the edge of Lada Terra. We report on the geologic units and structures and the sequence of events and, thus, the major stages in the evolution of this region of the midlands. At earlier stages of evolution of the long-wavelength topography, broad (hundreds of kilometers wide) and relatively low (1-1.5 km high) topographic ridges formed due to sequential development of deformation zones, first of contractional ridge belts (NW orientation) and then crosscut by extensional groove belts (NE orientation). Arcuate swarms of graben within groove belts often form the rims of coronae and represent their tectonic component. This suggests that groove belts and coronae within the quadrangle formed simultaneously. Intersections of these deformation zones caused separation of the topography of the region into a series of broad, shallow equidimensional basins many hundreds of kilometers across and currently hundreds of meters up to a kilometer deep. Thus, the principal topographic features within the quadrangle were established near the beginning of its observable geological record. The basins then remained sites of accumulation of successive volcanic plains units such as shield plains (psh) and the lower unit of regional plains (rp1). The flows of the younger plains, such as upper unit of regional plains (rp2) and lobate plains (pl), are less voluminous, and flow down the current topographic gradients. This implies that the major topographic pattern of the Fredegonde quadrangle has been stable since its establishment. Further evidence for this is that the vast volcanic plains units (psh and rp1) that postdate the heavily tectonized units of the deformation zones are only mildly deformed. This suggests that since the emplacement of shield plains, volcanism has been the primary geologic process and that the time of formation of unit psh corresponds to a major change from the earlier regime dominated by tectonics to the later volcanically dominated regime. Consistent age relationships among the main volcanic units within the quadrangle from older shield plains, through regional plains, to lobate plains, documents an evolution in volcanic style. Shield plains were formed from small eruptions from ubiquitous small shield volcanoes and are interpreted to be derived from broadly distributed and shallow magmatic sources. The lower unit of regional plains is widely distributed but vents and flow fronts are rare; this unit is interpreted to represent massive and probably short-lived flood basalts-like eruptions that filled in the lowlands basins. The upper unit of regional plains (rp2) and lobate plains (pl) are associated with localized and distinctive sources, such as late-stage volcanic activity at coronae. Thus, the tectonic stage of evolution of coronae (formation of the rims) and the volcanic stage when coronae served as magmatic centers and sourced lava flows, were separated in time by the emplacement of the shield and lower regional plains. How and when did the major components of Venus midland topography form? Clearly, in the Fredegonde quadrangle, regional deformation produced the deformation belts and groove belts/coronae in the earliest phases, and this topography formed the basis for the next, volcanic stage of emplacement (filling of the basins), with coronae-associated volcanism following this phase. The broad topography resulting from this early phase has persisted until the present. We compare this tectonic-volcanic sequence and history of topography in the Fredegonde quadrangle with other areas on Venus and find that the sequence has widespread application globally, and that the history of topography may be similar planet-w

Ivanov, Mikhail A.; Head, James W.

2012-12-01

189

Characterization of multiple prompt gamma-ray analysis (MPGA) system at JAEA for elemental analysis of geological and cosmochemical samples  

International Nuclear Information System (INIS)

The newly installed multiple prompt gamma-ray analysis (MPGA) system at the Japan Atomic Energy Agency (JAEA) was characterized for nondestructive multi-element analysis of geological and cosmochemical samples. Analysis of the hydrogenous meteorite Orgueil by both MPGA and PGA implies that MPGA can be used for elemental determination with sufficient accuracy. For some elements which cannot be determined by conventional PGA due to the spectral interference or lower sensitivity, it was shown that they could be determined by MPGA. - Highlights: ? Offline sorting modes of the coincidence data in MPGA were evaluated for elemental analyses. ? MPGA detection limits for some studied elements were improved around one order of magnitude than those obtained by other PGA facilities. ? For some elements, which cannot be determined by conventional PGA, it was observed that they could be determined by MPGA. ? Analysis of the hydrogenous meteorite Orgueil by MPGA implies that it can be used for elemental analysis with sufficient accuracy.

190

Isolation of gold from geological samples by microwave plasma for neutron activation analysis  

International Nuclear Information System (INIS)

A method for the isolation of gold from geological samples in microwave helium-oxygen plasma is produced as a preliminary step prior to the determination of gold by neutron activation analysis and gamma spectrometry. The study of the degree of chemical sublimation of gold in the plasma was carried out with samples that had been irradiated with neutrons. The dependence on the composition of the plasma support gas and on the time of treatment with the plasma is discussed. For the complete isolation (?95%) of gold the following optimum conditions were established: plasma support gas, helium-oxygen (40+60); flow-rate, 0.25 1 min-1; and time, 15 min. The isolated gold was transferred completely into tributyl phosphate as solid extractant, which was then analysed by neutron activation analysis and gamma spectrometry. The accuracy of the technique was checked using reference materials and the results agreed to within 10%. (author). 7 refs.; 3 figs

191

Constructive epistemic modeling of groundwater flow with geological structure and boundary condition uncertainty under the Bayesian paradigm  

Science.gov (United States)

Constructive epistemic modeling is the idea that our understanding of a natural system through a scientific model is a mental construct that continually develops through learning about and from the model. Using hierarchical Bayesian model averaging (BMA), this study shows that segregating different uncertain model components through a BMA tree of posterior model probability, model prediction, within-model variance, between-model variance and total model variance serves as a learning tool. First, the BMA tree of posterior model probabilities permits the comparative evaluation of the candidate propositions of each uncertain model component. Second, systemic model dissection is imperative for understanding the individual contribution of each uncertain model component to the model prediction and variance. Third, the hierarchical representation of the between-model variance facilitates the prioritization of the contribution of each uncertain model component to the overall model uncertainty. We illustrate these concepts using the groundwater flow model of a siliciclastic aquifer-fault system. We consider four uncertain model components. With respect to geological structure uncertainty, we consider three methods for reconstructing the hydrofacies architecture of the aquifer-fault system, and two formation dips. We consider two uncertain boundary conditions, each having two candidate propositions. Through combinatorial design, these four uncertain model components with their candidate propositions result in 24 base models. The study shows that hierarchical BMA analysis helps in advancing knowledge about the model rather than forcing the model to fit a particularly understanding or merely averaging several candidate models.

Elshall, Ahmed S.; Tsai, Frank T.-C.

2014-09-01

192

2005 dossier: granite. Tome: safety analysis of the geologic disposal; Dossier 2005: granite. Tome analyse de surete du stockage geologique  

Energy Technology Data Exchange (ETDEWEB)

This document makes a status of the researches carried out by the French national agency of radioactive wastes (ANDRA) about the safety aspects of the geologic disposal of high-level and long-lived (HLLL) radioactive wastes in granite formations. Content: 1 - safety approach: context and general goal, references, design approach by safety functions, safety approach during the construction-exploitation-observation-closure phase, safety analysis during the post-closure phase; 2 - general description: HLLL wastes, granitic environment, general structure of the architecture of a disposal facility; 3 - safety functions and disposal design: general context, safety functions of the long-term disposal, design dispositions retained to answer the functions; 4 - operational safety: people's protection, radiological risks during exploitation, risk analysis in accident situation; 5 - qualitative safety analysis: methodology, main results of the analysis of the features, events and processes (FEP) database; 6 - disposal efficiency evaluation during post-closure phase: calculation models, calculation tools used for the modeling of radionuclides transport, calculation results and main lessons. (J.S.)

NONE

2005-07-01

193

2D resistivity survey in complex geological structure area. Application to the volcanic area; Fukuzatsuna chishitsu kozo chiiki ni okeru hiteiko nijigen tansa. Kazangan chiiki deno tekiorei  

Energy Technology Data Exchange (ETDEWEB)

Introduced herein is an application of 2D resistivity survey to a volcanic rock area where the survey result is difficult to interpret because of its complex geological structure. In a dam site survey, main problems involve the permeability of water through faults and weathered, altered zones. At this site, a 2D resistivity survey was conducted, a 2D geological structure was deduced from the resistivity section, and the result was examined. It was found that resistivity distribution was closely related to hydrographic factors, but no obvious correlation was detected between rock classes and R, Q, and D. In conducting investigations into a section planned for a highway tunnel, it was learned that the problem was a volcanic ash layer to collapse instantly upon absorbing water, and the distribution of the ash layer, not to be disclosed by boring, was subjected to a 2D resistivity survey. The survey was conducted into the structure above where the tunnel would run, and further into the face, and studies were made about what layer was reflected by the resistivity distribution obtained by analysis. The result of the analysis agreed with the details of the layer that was disclosed afterward. 4 figs., 1 tab.

Asakawa, S.; Ikuma, T.; Tanifuji, R. [DIA Consultants Co. Ltd., Tokyo (Japan)

1996-05-01

194

A role of interconnected confined geological structural system in hydrothermal uranium mineralization and its significance in search of uranium deposit  

International Nuclear Information System (INIS)

This paper discussed an important metallogentic structural pattern of hydrothermal uranium deposit-the confined geological structural system interconnected with the inner part of the earth's crust. The so-called geological sturctural system is a general term for the sturctural passages that occurred in the shallow or deeper part of the earth's crust with confined migration to ground water (including hydrothermal solutions) connecting with the deep part (the anatectic zone) of the earth's crust by fractures, and its secondary permeable structure. It consists of alimentation area, confined migrating passage, passage of deep part, mixed area, drainage area, upper and lower barrier, etc. This geological structural system is important to hydrodthermal uranium mineralization in following aspects: it was favourable for the fromation of uranium-bearing hydrothermal solution; it could provide a kinetic condition for the migration of the uranium-bearing hydrothermal solution; it could dominate the particular position of forming-uranium mineralization; it could control the type of uranium mineralization, form, occurrence and buried depth of ore body

195

Geology of Kentucky  

Science.gov (United States)

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.

196

On risk analysis for repositories in northern Switzerland: extent and probability of geological processes and events  

International Nuclear Information System (INIS)

The literature study assesses, in the form of expert analysis, geological processes and events for a 1200 km2-area of northern Switzerland, with regard to repositories for medium- and high-active waste (depth 100 to 600 m and 600 to 2500 m, respectively) over the next 106 years. The area, which comprises parts of the Tabular Jura, the folded Jura and the Molasse Basin, the latter two being parts of the Alpine Orogene, has undergone a non-uniform geologic development since the Oligocene. Within the next 104 to 105 years a maximum earthquake intensity of VIII-IX (MSK-scale) has been predicted. After this period, particularly in the southern and eastern parts of the area, glaciations will probably occur, with associated erosion of possibly 200 to 300 m. Fluvial erosion as a reponse to an uplift could reach similar values after 105 to 106 years; however, there are no data on the recent relative vertical crustal movements of the area. The risk of a meteorite impact is considered small as compared to that of these factors. Seismic activity and the position and extent of faults are so poorly known within the area that the faulting probability cannot be derived at present. Flooding by the sea, intrusion of magma, diapirism, metamorphism and volcanic eruptions are not considered to be risk factors for final repositories in northern Switzerland. For the shallow-type repositories, the risk of denudation and landslides have to be judged when locality-bound projects have been proposed. (Auth.)

197

Coda-wave interferometry analysis of time-lapse VSP data for monitoring geological carbon sequestration  

Energy Technology Data Exchange (ETDEWEB)

Injection and movement/saturation of carbon dioxide (CO2) in a geological formation will cause changes in seismic velocities. We investigate the capability of coda-wave interferometry technique for estimating CO2-induced seismic velocity changes using time-lapse synthetic vertical seismic profiling (VSP) data and the field VSP datasets acquired for monitoring injected CO2 in a brine aquifer in Texas, USA. Synthetic VSP data are calculated using a finite-difference elastic-wave equation scheme and a layered model based on the elastic Marmousi model. A possible leakage scenario is simulated by introducing seismic velocity changes in a layer above the CO2 injection layer. We find that the leakage can be detected by the detection of a difference in seismograms recorded after the injection compared to those recorded before the injection at an earlier time in the seismogram than would be expected if there was no leakage. The absolute values of estimated mean velocity changes, from both synthetic and field VSP data, increase significantly for receiver positions approaching the top of a CO2 reservoir. Our results from field data suggest that the velocity changes caused by CO2 injection could be more than 10% and are consistent with results from a crosswell tomogram study. This study demonstrates that time-lapse VSP with coda-wave interferometry analysis can reliably and effectively monitor geological carbon sequestration.

Zhou, R.; Huang, L.; Rutledge, J.T.; Fehler, M.; Daley, T.M.; Majer, E.L.

2009-11-01

198

Parametric uncertainty analysis using Latin Hypercube Sampling in risk assessment of deep geological HLW repository  

International Nuclear Information System (INIS)

With regard to the safety assessment of deep geological HLW repository, there may be many parameters subject to uncertainty. Dilution factor is considered as a parameter that has large uncertainty in this study. Under the assumption that PWR spent fuels are disposed of into deep geological repository, uncertainty analysis on dilution factor has performed. Deterministic calculation of radionuclides transport through geosphere is performed preliminarily. To analyze the uncertainty of dilution factor, lognormal distribution is assumed with range from 4 to 100,000 and Latin Hypercube Sampling (LHS) is used for sampling. Finally, annual individual dose calculated with sampled dilution factor and the histogram of peaks of annual individual doses is proved to have lognormal distribution by chi-square test. Lower and upper limits of annual individual dose are shown with 95% confidence level. Uncertainty of dose resulted from wide range of dilution factor may cause large difference between lower and upper limit up to four order of magnitude. In the condition of low dilution in geosphere, the annual individual dose is even up to 10-4 mSv/yr. (author)

199

Analysis of geological condition and prospecting potential of uranium metallogenesis in Maling granite mass  

International Nuclear Information System (INIS)

Based on the study of regional geological evolution of Maling granite mass, uranium content of granite mass and its peripheric strata, petrogeochemistry and the known spatial distribution pattern of uranium mineralization and ore-controlling structures, new recognition is 1) Maling composite mass is the 'S' type re-melted granite, 2) the accumulative area of regional uranium metallogenic substances forms uranium-rich re-melted strata, 3) magma evolution is the matter base for the uranium-rich hydrotherm, 4) NE-trending main faults are channels for metallogenesis and the lateral high-angle dipping faults, fractures and interlayer fractures in the peripheric strata are the spaces of mineralization. The ore intersected by drilling in Maling granite is acidic type. Prospecting potential of Maling granite mass is analyzed, and preferable prospecting space is delineated for further exploration. (authors)

200

Thai Rhetorical Structure Analysis  

CERN Document Server

A rhetorical structure tree (RS tree) is a representation of discourse relations among elementary discourse units (EDUs). A RS tree is very useful to many text processing tasks employing relationships among EDUs such as text understanding, summarization, and question answering. Thai language with its unique linguistic characteristics requires a unique RS tree construction technique. This paper proposes an approach for Thai RS tree construction which consists of three major steps: EDU segmentation, Thai RS tree construction, and discourse relation (DR) identification. Two hidden markov models derived from grammatical rules are used to segment EDUs, a clustering technique with its similarity measure derived from Thai semantic rules is used to construct a Thai RS tree, and a decision tree whose features extracted from the rules is used to determine the DR between EDUs. The proposed technique is evaluated using three Thai corpora. The results show the Thai RS tree construction and the DR identification effectiven...

Sinthupoun, Somnuk

2010-01-01

 
 
 
 
201

Multidimensional inversion of MT data from Alid Geothermal area, Eritrea. Comparison with geological structures and identification of a geothermal reservoir  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Electrical resistivity methods have been the most powerful tool in geothermal exploration for decades. Of these, MT and TEM are important methods in delineating geothermal resources. The main objective of this study is to understand the nature (dimensionality) of the MT data from Alid Geothermal area, Eritrea and apply multidimensional inversion to the data and compare the result with geological structures and the identification of a geothermal reservoir. In this project, 47 M...

Teklesenbet, Andemariam

2012-01-01

202

Collapse Analysis of Timber Structures  

DEFF Research Database (Denmark)

A probabilistic based collapse analysis has been performed for a glulam frame structure supporting the roof over the main court in a Norwegian sports centre. The robustness analysis is based on the framework for robustness analysis introduced in the Danish Code of Practice for the Safety of Structures and a probabilistic modelling of the timber material proposed in the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS). Due to the framework in the Danish Code the timber structure has to be evaluated with respect to the following criteria where at least one shall be fulfilled: a) demonstrating that those parts of the structure essential for the safety only have little sensitivity with respect to unintentional loads and defects, or b) demonstrating a load case with „removal of a limited part of the structure? in order to document that an extensive failure of the structure will not occur if a limited part of the structure fails, or c) demonstrating sufficient safety of key elements, such that the entire structure with one or more key elements has the same reliability as a structure where robustness is documented by b). Based on investigations with respect to criteria a) and b) the timber frame structure has one column with a reliability index a bit lower than an assumed target level. By removal three columns one by one no significant extensive failure of the entire structure or significant parts of it are obtained. Therefore the structure can be considered to behave robust according to the sued probabilistic approach. However, the present probabilistic approach for robustness evaluation has to be further developed for a general application to timber systems, and a simplified approach suitable for day-to-day engineering purposes must be identified.

Kirkegaard, Poul Henning; SØrensen, John Dalsgaard

2008-01-01

203

Overview of the structural geology and tectonics of the Central Basin Platform, Delaware Basin, and Midland Basin, West Texas and New Mexico  

Energy Technology Data Exchange (ETDEWEB)

The structural geology and tectonics of the Permian Basin were investigated using an integrated approach incorporating satellite imagery, aeromagnetics, gravity, seismic, regional subsurface mapping and published literature. The two primary emphases were on: (1) delineating the temporal and spatial evolution of the regional stress state; and (2) calculating the amount of regional shortening or contraction. Secondary objectives included delineation of basement and shallower fault zones, identification of structural style, characterization of fractured zones, analysis of surficial linear features on satellite imagery and their correlation to deeper structures. Gandu Unit, also known as Andector Field at the Ellenburger level and Goldsmith Field at Permian and younger reservoir horizons, is the primary area of interest and lies in the northern part of Ector county. The field trends northwest across the county line into Andrews County. The field(s) are located along an Ellenburger thrust anticline trap on the eastern margin of the Central Basin Platform.

Hoak, T. [Kestrel Geoscience, Littleton, CO (United States); Sundberg, K. [Phillips Petroleum Co., Bartlesville, OK (United States); Ortoleva, P. [Indiana Univ., Bloomington, IN (United States)

1998-12-31

204

SG2PS (structural geology to postscript converter) - A graphical solution for brittle structural data evaluation and paleostress calculation  

Science.gov (United States)

The aim of this work was to create an open source cross platform application to process brittle structural geological data with seven paleostress inversion algorithms published by different authors and formerly not available within a single desktop application. The tool facilitates separate processing and plotting of different localities, data types and user made groups, using the same single input file. Simplified data input is supported, requiring as small amount of data as possible. Data rotation to correct for bedding tilting, rotation with paleomagnetic declination and k-means clustering are available. RUP and ANG stress estimators calculation and visualization, resolved shear direction display and Mohr circle stress visualization are available. RGB-colored vector graphical outputs are automatically generated in Encapsulated PostScript and Portable Document Format. Stereographical displays on great circle or pole point plot, equal area or equal angle net and upper or lower hemisphere projections are implemented. Rose plots displaying dip direction or strike, with dip angle distribution of the input data set are available. This tool is ideal for preliminary data interpretation on the field (quick processing and visualization in seconds); the implemented methods can be regularly used in the daily academic and industrial work as well. The authors' goal was to create an open source and self-contained desktop application that does not require any additional third party framework (such as .NET) or the Java Virtual Machine. The software has a clear and highly modular structure enabling good code portability, easy maintainability, reusability and extensibility. A Windows installer is publicly available and the program is also fully functional on Linux. The Mac OS X port should be feasible with minimal effort. The install file with test and demo data sets, detailed manual, and links to the GitHub repositories are available on the regularly updated website www.sg2ps.eu.

Sasvári, Ágoston; Baharev, Ali

2014-05-01

205

Phylogeographic structure in an Australian freshwater shrimp largely pre-dates the geological origins of its landscape.  

Science.gov (United States)

The phylogeographic structure of cryptic lineages within the freshwater shrimp Caridina indistincta Calman, 1926 (Decapoda: Atyidae) was investigated in an attempt to unravel any potential genetic influences of Quaternary sea-level oscillations. The study was based on mitochondrial DNA sequences from specimens from lakes and creeks in the sand dune areas of southeast Queensland, eastern Australia. Four divergent lineages were identified, two of which were from Moreton and North (N.) Stradbroke Islands. Lineage 'C1' has been found only on Moreton Island and the western part of N. Stradbroke Island, whereas 'C2' was found on the eastern side of N. Stradbroke Island and a few locations on the mainland. These diverged from each other during the Late Miocene/Pliocene and so are older than the current landscape in which they are found. Small-scale phylogeographic analysis of C1 identified four separate geographic areas, within the two islands, whose divergences date to the Pleistocene (approximately 100-300 thousand years ago ('kya')). The N. Stradbroke Island population of C2 also diverged from the mainland during the Pleistocene, as did a sympatric freshwater fish Rhadinocentrus ornatus Regan, 1914 (Melanotaeniidae). This implies that the ice-age sea-level changes may have structured these populations, although there is little observable influence of the last glacial maximum (approximately 18 kya). Most estimates for the age of the landscape (dunes, lakes) also fall within the Pleistocene and so the effect of sea-level change may be seen both in biology and geology. PMID:17213864

Page, T J; Hughes, J M

2007-04-01

206

Sequence stratigraphic analysis and integrated 3D geological modeling of M1 block, Wenmingzhai oilfield, Dongpu depression, China  

Science.gov (United States)

The M1 block is a typically complex fault-block oilfield, whose recovery has reached 30.5% through the twenty years waterflooding development. Remaining oil scatters very widely and the production between layers is in a high degree. However, many problems have been exposed at the same time which hinder improvement of the recovery rate and sustainable development of the reservoir. Hence, it is important to carry out basic geological research and form a comprehensive understanding of reservoir properties. However, few such studies have been conducted in China. In this study, work related to basic geological research was conducted based on high-resolution sequence stratigraphy, seismic interpretation technology and 3D visual geological modeling, and significant results were achieved. Three sequence orders and three types of interfacies in the stratigraphic architecture of M1 block were identified through seismic sections, logging curve characteristics and entropy spectrum analysis. Thirty-two short-term sequence cycles (fifth order), eight mid-term sequence cycles (fourth order) and two long-term sequence cycles (third order) were identified, followed by the establishment of a high-resolution isochronous stratigraphic correlation framework. Finally, a regional 3D geological model was established on the basis of these preliminary studies. The integrated 3D geological model is a valuable tool for reflecting geological bodies accurately, and it can accurately represent and describe reservoir heterogeneity.

Li, Xue; Zhang, Jinliang; Yuan, Yong; Li, Cunlei; Meng, Ningning

2013-09-01

207

Rare earths in environment and geologic samples determined by neutron activation analysis  

International Nuclear Information System (INIS)

Neutron activation analysis allows to determine rare earth elements (REE) with a sensivity much higher than non-nuclear methods. In this work, this technique has been applied to the determination of REE in environmental samples, such as marine suspended particulate matter and sea, lake and river sediments. The importance of lanthanides in the environmental field is due to the fact that some REE, because of their nearly identical physico-chemical behaviour, can simulate the environmental behaviour of actinides, generated by activation or fission processes. Am(III) can be simulated by Eu(III) and Nd(III), that can simulate also Cm(III). As regardes REE in geological studies, their distribution and fractionation in rocks provide information about the genesis and the evolution of the rocks themselves. In this work, some data relevant to Kenya rocks are presented

208

Characterization of Geologic Structures and Host Rock Properties Relevant to the Hydrogeology of the Standard Mine in Elk Basin, Gunnison County, Colorado  

Science.gov (United States)

The Standard Mine Superfund Site is a source of mine drainage and associated heavy metal contamination of surface and groundwaters. The site contains Tertiary polymetallic quartz veins and fault zones that host precious and base metal sulfide mineralization common in Colorado. To assist the U.S. Environmental Protection Agency in its effort to remediate mine-related contamination, we characterized geologic structures, host rocks, and their potential hydraulic properties to better understand the sources of contaminants and the local hydrogeology. Real time kinematic and handheld global positioning systems were used to locate and map precisely the geometry of the surface traces of structures and mine-related features, such as portals. New reconnaissance geologic mapping, field and x-ray diffraction mineralogy, rock sample collection, thin-section analysis, and elemental geochemical analysis were completed to characterize hydrothermal alteration, mineralization, and subsequent leaching of metallic phases. Surface and subsurface observations, fault vein and fracture network characterization, borehole geophysical logging, and mercury injection capillary entry pressure data were used to document potential controls on the hydrologic system.

Caine, Jonathan S.; Manning, Andrew H.; Berger, Byron R.; Kremer, Yannick; Guzman, Mario A.; Eberl, Dennis D.; Schuller, Kathryn

2010-01-01

209

Analysis of geological aspects and visual impact rising from the realisation of a wind power station in an Italian mountain area (Central Appennines)  

International Nuclear Information System (INIS)

This study evaluates some aspects of the environmental impacts arising from the wind power station in the Central Appennines of Italy, particularly with reference to the geological and geotechnical conditions of the site and the visual impact on the landscape. Starting from a large-scale analysis that takes into account the Appennines orogeny and their geodynamic process, it is possible to define the geological characteristics of the considered area. It is possible to analyse structural and morphological aspects, in this way it is possible to identify the most suitable location of power generators in the area and to optimise the road network. The geo-stratigraphical study aids decisions about foundations, excavations and works of containments. Considerations on earth traspiration and on rill identify the necessity of controlling surface waters, evolutionary phenomena and the soil stability of the considered areas. Particular attention has been given to analyse effects on the landscape. (author)

210

Crustal structure across the San Andreas Fault at the SAFOD site from potential field and geologic studies  

Science.gov (United States)

We present newly compiled magnetic, gravity, and geologic datasets from the Parkfield region around the San Andreas Fault Observatory at Depth (SAFOD) pilot hole in order to help define the structure and geophysical setting of the San Andreas Fault (SAF). A 2-D cross section of the SAF zone at SAFOD, based on new, tightly spaced magnetic and gravity observations and surface geology, shows that as drilling proceeds NE toward the SAF, it is likely that at least 2 fault bounded magnetic slivers, possibly consisting of magnetic granitic rock, serpentinite, or unusually magnetic sandstone, will be encountered. The upper 2 km of the model is constrained by an order of magnitude increase in magnetic susceptibility at 1400 m depth observed in pilot hole measurements. NE of the SAF, a flat lying, tabular body of serpentinite at 2 km depth separates two masses of Franciscan rock and truncates against the SAF.

McPhee, D.K.; Jachens, R.C.; Wentworth, C.M.

2004-01-01

211

Quantification of rock heterogeneities by structural geological field studies combined with laboratory analyses  

Science.gov (United States)

Heterogeneous rock properties in terms of layering and complex infrastructure of fault zones are typical in sedimentary successions. The knowledge of in-situ mechanical rock properties is crucial for a better understanding of processes such as fracturing and fluid transport in fractured reservoirs. To estimate in situ rock properties at different depths it is important to understand how rocks from outcrops differ from rocks at depth, for example due to alteration and removal of the overburden load. We aim at quantifying these properties by performing structural geological field studies in outcrop analogues combined with laboratory analyses of outcrop samples and drill-cores. The field studies focus on 1) fault zone infrastructure and 2) host rock fracture systems in two different study areas with different lithologies, the North German and the Bristol Channel Basin. We analyse quantitatively the dimension, geometry, persistence and connectivity of fracture systems. The field studies are complemented by systematic sampling to obtain the parameters Young's modulus, compressive and tensile strengths and elastic strain energy (also referred to as destruction work) from which we estimate rock and fracture toughnesses. The results show that in rocks with distinctive layering fractures are often restricted to individual layers, that is, stratabound. The probability of arrest seems to depend on the stiffness contrast between two single layers as well as on the thickness of the softer layer. The results also show that there are clear differences between fault zones in the different lithologies in terms of damage zone thicknesses and fracture system parameters. The results of laboratory analyses show that the mechanical properties vary considerably and for many samples there are clear directional differences. That is, samples taken perpendicular to layering commonly have higher stiffnesses and strengths than those taken parallel to layering. We combine the results of laboratory analyses and field measurements to specify the mechanical heterogeneities of typical sedimentary rocks and of the mechanical units of fault zones. The results from drill-core sample analyses are then compared with the results from the outcrop samples. Another approach is to analyse how rock mechanical properties correlate with petrographic properties (e.g., mineral content, cementation, fabric) to use this knowledge to extrapolate the data to depth. Acknowledgements The authors appreciate the support of 'Niedersächsisches Ministerium für Wissenschaft und Kultur' and 'Baker Hughes' within the gebo research project (http://www.gebo-nds.de). The project "Fracture propagation and reservoir permeability in limestone-marl alternations" is funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, http://www.dfg.de).

Reyer, Dorothea; Afsar, Filiz; Philipp, Sonja

2013-04-01

212

The advanced scenario analysis for performance assessment of geological disposal. 2  

International Nuclear Information System (INIS)

As the first step of this study, description level and content of the FEPs (Feature, Event, Process) with regard to the FEP information data on the Natural Barrier System developed by JNC have been examined from various angles on the basis of the latest research information. Each content of the FEP data has been classified and modified by means of integrating descriptive items, checking detail levels and correlations with other FEPs, collating with the H12 report, and adding technical information after H12 report. Secondly, scenario analysis method has been studied. As an illustrated example, a procedure for deriving a calculation case by using Connectivity Matrix and PPM (Parameters, Processes, Models) database was applied for buffer in base scenario and then volcanism scenario. Also, another approach based on Correlation Matrix has been comparatively discussed to list up future subjects. Lastly, in relation to the geological disposal system, assessment techniques have been examined for more practical scenario analysis on variant scenario. Possible conceptual models have been proposed for uplift and erosion scenario. As a result of these researches, a future direction for advanced scenario analysis on performance assessment has been indicated, as well as associated issues to be discussed have been clarified. (author)

213

Summary report of the advanced scenario analysis for performance assessment of geological disposal  

International Nuclear Information System (INIS)

First of all, with regard to the FEP information data on the Engineered Barrier System (EBS) developed by JNC, description level and content of the FEPs have been examined from various angles on the basis of the latest research information. Each content of the FEP data has been classified and modified by means of integrating descriptive items, checking detail levels and correlations with other FEPs, collating with the H12 report, and adding technical information after H12 report. Secondly, scenario-modeling process has been studied. The study has been conducted by evaluating representation of the repository system, definition of FEP properties, and process interactions based on the concept of the interaction matrix (RES format) which represents influences between physicochemical characteristics of the repository, followed by an experimental development of the actual RES interaction matrix based on the H12 report as the examination to improve the transparency, traceability and comprehensibility of the scenario analysis process. Lastly, in relation to the geological disposal system, assessment techniques have been examined for more practical scenario analysis on particularly strong perturbations. Possible conceptual models have been proposed for each of these scenarios; seismic, faulting, and dike intrusion. As a result of these researches, a future direction for advanced scenario analysis on performance assessment has been indicated, as well as associated issues to be discussed have been clarified. (author)

214

Neutron-activation analysis of several US Geological Survey and National Bureau of Standards reference materials  

International Nuclear Information System (INIS)

In this work, several US Geological Survey (U.S.G.S.) and National Bureau of Standards (N.B.S.) reference samples have been analyzed in an effort to improve the quality of elemental concentration data available on these materials, so they can be used in a program of verification of factor analysis source resolution procedures. The analyses of these samples were performed by instrumental neutron activation analysis (INAA). The samples analyzed were: U.S.G.S. Green River Shale, N.B.S. 45b Homogeneous River Sediment, U.S.G.S. Analyzed Peridotite N.B.S. 1579 Powdered Lead-based Paint, U.S.G.S. Hawaian Basalt U.S.G.S. Marine Mud, U.S.G.S. Analyzed Cody Shale U.S.G.S. Glass Mountain Rhyolite, N.B.S. Argillaceous Limestone No. 1, and a sample of Spex ultrapure graphite. Neutron activation analysis was employed because of the high sensitivity that can be attained in determining elemental concentrations. Although INAA is a relatively simple method and the reproducibility of the data is good, the method shows some inaccuracies. The basic theory and technique are reviewed in an attempt to show where problems can arise and how they can be dealt with

215

Neutron-activation analysis of geologic samples for gold and associated elements using a power reactor  

International Nuclear Information System (INIS)

The method of neutron-activation analysis (NAA) using research reactors as neutron sources is widely used in the elemental analysis of rocks and ores. Because of the limited access to research reactors, however, it is difficult case, power reactors are promising for use in NAA. The authors investigated the possibility of using a power reactor for NAA of geological samples for gold and associated elements. Because of the difficult access to the channels passing through the active zone of the reactor, the samples were irradiated in the reserve channel for ionization chambers situated outside the active zone in the graphite reflector. The determination of gold by the NAA method is based on the radiative capture reaction 197Au(n, ?)198Au (T12 = 65 h) and subsequent detection of 412-keV ? rays. Gold containing samples and standards pulverized to a particle size of 200 mesh were prepared for the analysis. The sensitivity thresholds of a wide range of elements accompanying gold, which are well activated by thermal and resonance neutrons, were also evaluated

216

An engineering geological appraisal of the Chamshir dam foundation using DMR classification and kinematic analysis, southwest of Iran  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: English Abstract in spanish Este articulo describe los resultados de una investigación de ingeniería geológica y estudios de mecánica de roca que se llevo a cabo en el lugar propuesto para le represa Chamshir. Se propone una presa de 155m de altura, de arco gravitacional en concreto de solido, la cua debe ser construida a trav [...] és del rio Zuhreh al sureste de la ciudad de Gachsaran en el suroeste de Irán. La presa y su estructura asociada son localizadas principalmente sobre la formación Mishan. El análisis consistió en la clasificación del macizo rocoso y un análisis cinemático de la fundación de la masa rocosa de la presa. Los estudios se llevaron a cabo en campo y laboratorio. Los estudios de campo incluyeron cartografía geológica, un estudio intensivo de discontinuidad, perforación de núcleo y toma de muestras para pruebas de laboratorio. La clasificación de la masa rocosa se realizo de acuerdo con la clasificación RMR y DMR para la fundación de la presa. El análisis de basamento rocoso de la presa en relación a la estabilidad usando la clasificación DMR y el análisis cinemático indico que el estribo izquierdo del basamento (área 2) es inestable para tipos de fallo planares y de cuña. Abstract in english This paper describes the results of engineering geological investigations and rock mechanics studies carried out at the proposed Chamshir dam site. It is proposed that a 155 m high solid concrete gravity-arc dam be built across the Zuhreh River to the southeast of the city of Gachsaran in south-west [...] ern Iran. The dam and its associated structures are mainly located on the Mishan formation. Analysis consisted of rock mass classification and a kinematic analysis of the dam foundation's rock masses. The studies were carried out in the field and the laboratory. The field studies included geological mapping, intensive discontinuity surveying, core drilling and sampling for laboratory testing. Rock mass classifications were made in line with RMR and DMR classification for the dam foundation. Dam foundation analysis regarding stability using DMR classification and kinematic analysis indicated that the left abutment's rock foundation (area 2) was unstable for planar, wedge and toppling failure modes.

Mehdi, Torabi Kaveh; Mojtaba, Heidari.

2011-12-01

217

Dinosaur tectonics : structural geology as a tool to interpret theropod walking dynamics  

DEFF Research Database (Denmark)

A dinosaur trackway in the Middle Jurassic eolian Entrada Sandstone of southern Utah, USA, exposes three undertracks that we have modeled as isolated tectonic regimes showing the development of fold-thrust ramp systems induced by the dinosaur's feet. The faulted and folded sequence is comparable to crustal scale tectonics associated with plate tectonics and foreland fold-thrust belts. A structural analysis of the dinosaur tracks shows the timing and direction of the forces exercised on the substrate by the animal's foot during the stride. Based on the structural analysis, we establish a scenario for foot movements and weight distribution in the feet. During the end of the weight-bearing phase of the stride, the weight of the animal was transferred to the front of the digits, creating a rotated disc below the foot that was bounded by an extensional fault at the front and a thrust ramp toward the back. As the body accelerated, the foot was forced backward. The rotated disc was forced backward along a detachmentfault that was bounded by lateral ramps. The interramp segment matches the width of the dinosaur's foot which created an imbricate fan thrust system that extended to the far end of the undertrack. The total length of the tectonic disturbance created by the dinosaur is up to three times that of the original footprint. Early, near-surface cementation gave the substrate the rheological properties necessary for development of the observed structures.

Graversen, Ole; Milàn, Jesper

2007-01-01

218

The Beaverhead impact structure, SW Montana and Idaho: Implications for the regional geology of the western U.S.  

Energy Technology Data Exchange (ETDEWEB)

The Beaverhead impact structure in SW Montana and Idaho is an allochthonous fragment of a large impact structure ({approximately} 100 km diameter) that was transported some distance eastward during the Cretaceous Sevier orogeny. It is the first tectonic fragment of a large impact structure identified in the geologic record. The present evidence for impact consists of shatter cones, pseudotachylites, and planar deformation features in quartz. The age of the impact is not well constrained but is estimated to be Neoproterozoic to Cambrian (1000-500 Ma). The Beaverhead impact event must have created other features that may be preserved, elsewhere in western Montana and Idaho. These include proximal and distal ejecta (which may be misinterpreted as diamictites and/or tuff horizons) and other fragments of the crater floor containing shatter cones and pseudotachylite. A large circular gravity, magnetic and topographic anomaly, which could be the root of the impact structure, has been identified near Challis, Idaho. An enigmatic lithic tuff, identified in drill cores from the Challis area and an intraformational quartzite breccia in the Leaton Gulch area may be impact-related deposits, but no definitive evidence of shock metamorphism has been observed in these materials. The discovery of more pieces of the Beaverhead puzzle, as well as the recognition of other large impacts in the geologic record, are likely once the regional geologic community grows to accept the incidence of such events and becomes more familiar with the features of shock metamorphism in the field. To that end, the community of geologists in this area should integrate the Beaverhead structure into their research and teaching curriculum.

Fiske, P.S.; Hargaves, R.B.

1994-03-17

219

GEMAS results from the Pannonian Basin - geochemical signatures in a transnational geological structure  

Science.gov (United States)

The Pannonian Basin, also referred to as Carpathian Basin, has its geological origins in the Pannonian Sea which was part of the Parathetys Sea, from which it was separated around 10 Ma ago. It spreads over large part of the southeastern part of Central Europe. The centre of the Pannonian Basin is located in Hungary and extends to the adjoining countries Austria, Slovakia, Romania, Ukraine, Croatia, Serbia, Slovenia and Bosnia-Herzegovina. The basin is surrounded by the Carpathian Mountains, the Alps, the Dinarides and the Balkan mountains. The Pannonian Basin is filled by Molasse sediments, which were deposited during the Alpine orogenesis and originating from the rising Alpine and Carpathian Mountain chains. The orogenesis continued during the sedimentation into the Molasse basin. The tectonic movements resulted in several cycles of trans- and regressions of the Parathetys, the sedimentation of marine and freshwater sediments as well as a multitude of fractures and cleavages during the orogensis and the subsidence of different parts of the basin. Even if the Pannonian Basin was formed during a complex orogenesis, it can be regarded as a geo- and hydrodynamic unit. In accordance with the geological history, the soils in the Pannonian Basin developed on loose sediments - including significant loess deposits - and are dominated by soil types which also reflect the continental and steppe climate in this area - Planosols, Luvisols, Cambisols, Calcisols, Chernozems and Phaeozems. The basin is extensively used for agricultural purposes. The geochemical patterns Pannonian Basin are considerably different compared to its surroundings due to its geological development. The spatial distribution of some elements (REE (La, Ce), Y, Th, V, Cd, Pb) are clearly different inside and outside the basin area. For this transnational geological and geographical area, the GEMAS results are compiled and multivariate statistics are applied to find common geochemical signatures in relation to the geological history of the Basin.

Haslinger, Edith; Jordan, Gyozo; Slaninka, Igor; Sorsa, Ajka; Gulan, Aleksandra; Gosar, Mateja; Hratovic, Hazim; Klos, Volodymyr

2014-05-01

220

Seismic and structural geology constraints to the selection of CO2 storage sites - the case of the onshore Lusitanian basin, Portugal  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Lusitanian sedimentary basin, in Portugal, has a complex tectonic history and a seismic activity determined by the proximity to the Eurasian – Nubian tectonic plate boundary. Seismic activity and geological structure impose serious constraints to the selection of CO2 storage sites. This article focuses on the constraints imposed by active seismicity, geological structure and, as a direct consequence of the latter, by the hydrogeology and geothermal framework, to the identification of on...

Pereira, Nadine; Carneiro, Ju?lio; Arau?jo, Alexandre; Bezzeghoud, Mourad; Borges, Jose?

2013-01-01

 
 
 
 
221

Arbitral analysis of uranium in sandstone uranium geological samples by isotope dilution inductively coupled plasma mass spectrometery  

International Nuclear Information System (INIS)

A method for determination of uranium in sandstone uranium geological samples by isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) was evaluated. Samples were digested and spiked with highly enriched uranium (HEU) in a closed vessel using mixed acids, and 235U/238U ratio was measured by high resolution ICP-MS. The method is capable of determining uranium contents of 1-10 000 ?g/g with relative expanded uncertainty of 4.0% at uranium contents of 4 ?g/g, and is qualified for the arbitral analysis of uranium in sandstone uranium geological samples. (authors)

222

In-Situ XRF analysis of environmental, geological and archaeological samples  

International Nuclear Information System (INIS)

The paper presents some considerations and preliminary results on using the portable X-ray fluorescence spectrometry as in-situ method for the analysis of solid samples of environmental, geological or archaeological origin. Field portable x-ray fluorescence (FPXRF) is an exemplary field method, offering extremely rapid, versatile screening by in-situ measurement with accuracy that can rival that of standard laboratory analysis, despite the low detection limits are higher than the limits of detection (LODs) attained by laboratory. Generally elements of atomic number 12 or greater up to elements as Thorium (Th) and Uranium (U) can be detected and quantitated by FPXRF. Detection limits depend on several factors, the analyte of interest, the type of detector used, the type of excitation source, the strength of the excitation source, counting times used to irradiate the sample, physical matrix effects, chemical matrix effects, and interelement spectral interferences. These detection limits are given for guidance only and will vary depending on the sample matrix, which instrument is used, and operating conditions, important for such samples as those considered. (authors)

223

Instrumental neutron activation analysis of Moroccan geological samples using the k0-standardization method  

International Nuclear Information System (INIS)

Instrumental neutron activation analysis (INAA) for traces and major elements of several geological samples from 'Zgounder' region in Morocco was performed utilizing the k0-standardization method. Sample irradiation has been done by the 250 kW Triga Mark II reactor at Jozef Stefan Institute in Slovenia. Due to its accuracy, sensitivity and specificity, the k0-standardization method is the most suitable method for non-destructive multielement analysis mainly for trace elements in rocks. It requires an accurate knowledge of the parameters of the irradiation facilities and other instrumentation parameters. It is an absolute standardization method, where the absolute nuclear data are replaced by a nuclear constant, the k0-factor, determined experimentally with high accuracy. More than 40 elements were determined using about 30-second short and about 7-hour long irradiations. Gamma-rays emitted from the irradiated samples have been determined by a high purity germanium detector. Accuracy was assessed using the standard reference material AGV-1. This was less than 1% for major elements and about 5% for traces. (author)

224

Sodium loop framework structural analysis  

International Nuclear Information System (INIS)

This document provides the structural analysis of the Sodium Loop framework in a drop condition. The drop is similar to the US Department of Transportation non-bulk, performance-oriented packaging (Packaging Group I) drop test. The drop height evaluated for the Sodium Loop framework is 5.9 ft

225

Structural analysis of a Tippler structure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tippler structures operate under arduous conditions for most of their operational lives. During routine structural inspections large fatigue cracks were discovered on some of the main structural components of a Tippler structure. These cracks were situated in a safety-critical area of the structure and therefore rendered the structure unsafe for operation. Structural failure could affect throughput enormously as the Tippler forms the first step in a coal terminal’s operational process. A hi...

Zyl, Petrus Johannes Adriaan

2005-01-01

226

Azimuth F inder: a software for data reading in structural geology  

Directory of Open Access Journals (Sweden)

Full Text Available Here is presented a computational tool named AzimuthFinder, for functioning inside the set of programs of ArcGis®. The developed program is intended to facilitate and optimize the generation of azimuth data tables, using structural lineaments previously traced in maps that are being worked on that automatic information system. The characteristics of AzimuthFinder allow that, upon the user’s choice, different tables get generated for the same analysis object, depending on the relative weight attributed to the lineaments, giving for example greater weight to those of greater extension. Another characteristic of the tool is the file exportation in TXT format, which is universal to several types of programs, with specific formatting to one the software between Stereo32, Win Tensor, OpenStereo and StereoNet7, which are all free software prepared to the confection of rose diagrams. Tests with the program showed that it is very efficient and fast for generating the azimuth data tables, effectively allowing easier confection of rose diagrams, which are necessary for the structural analysis in areas submitted to fragile deformation.

Gustavo Lopes Queiroz

2014-03-01

227

Reactor neutron activation analysis of geological samples and a comparison with other non-nuclear analytical techniques  

International Nuclear Information System (INIS)

The status of neutron activation analysis (NAA) in geological research is discussed. The technique was developed as far back as the beginning of the 1970s, though since then no improvement in detectable elements or accuracy has taken place. Approximately 40 elements can be analysed by instrumental activation analysis. By applying radiochemical separation, the number of elements that can be analysed increases to almost 70. Compared with other analytical methods used in geological research, activation analysis has some unique features. It thus continues to have a strong position in basic geochemical research. About half of all the publications dealing with basic research includes activation analysis determinations. In routine geochemical surveys and mineral exploration, NAA is much less frequently used. However, a few examples of geochemical surveys, especially for uranium, but also gold and other elements, can be found in the literature. (author). 48 refs, 8 tabs

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  

Science.gov (United States)

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

Safety analysis of geologic containment of long life radioactive wastes. Critical assessment of existing methods and proposition of prospective approach  

International Nuclear Information System (INIS)

Existing methods of risk analysis applied to disposal of long-lived radioactive waste in geologic formations are rewieved. A prospective analysis method for containment performances is proposed, deduced in the burial system from the combination of interaction between wastes, repository, host rock, surrounding geosphere, of natural evolution of each component of the system, sudden or chance events that could break waste containment. The method is based on the elaboration of four basic schemes graded in difficulties to facilitate comparisons

230

Analysis on the use of engineered barriers for geologic isolation of spent fuel in a reference salt site repository  

Energy Technology Data Exchange (ETDEWEB)

A perspective on the potential durability and effectiveness requirements for the waste form, container and other engineered barriers for geologic disposal of spent nuclear fuel has been developed. This perspective is based on calculated potential doses to individuals who may be exposed to radioactivity released from a repository via a groundwater transport pathway. These potential dose commitments were calculated with an integrated geosphere transport and bioshpere transport model. A sensitivity analysis was accomplished by varying four important system parameters, namely the waste radionuclide release rate from the repository, the delay prior to groundwater contact with the waste (leach initiation), aquifer flow velocity and flow path length. The nuclide retarding capacity of the geologic media, a major determinant of the isolation effectiveness, was not varied as a parameter but was held constant for a particular reference site. This analysis is limited to looking only at engineered barriers whose net effect is either to delay groundwater contact with the waste form or to limit the rate of release of radionuclides into the groundwater once contact has occurred. The analysis considers only leach incident scenarios, including a water well intrusion into the groundwater near a repository, but does not consider other human intrusion events or catastrophic events. The analysis has so far been applied to a reference salt site repository system and conclusions are presented.Basically, in nearly all cases, the regional geology is the most effective barrier to release of radionuclides to the biosphere; however, for long-lived isotopes of carbon, technetium and iodine, which were poorly sorbed on the geologic media, the geology is not very effective once a leach incident is initiated.

Cloninger, M.O.; Cole, C.R.; Washburn, J.F.

1980-12-01

231

Analysis on the use of engineered barriers for geologic isolation of spent fuel in a reference salt site repository  

International Nuclear Information System (INIS)

A perspective on the potential durability and effectiveness requirements for the waste form, container and other engineered barriers for geologic disposal of spent nuclear fuel has been developed. This perspective is based on calculated potential doses to individuals who may be exposed to radioactivity released from a repository via a groundwater transport pathway. These potential dose commitments were calculated with an integrated geosphere transport and bioshpere transport model. A sensitivity analysis was accomplished by varying four important system parameters, namely the waste radionuclide release rate from the repository, the delay prior to groundwater contact with the waste (leach initiation), aquifer flow velocity and flow path length. The nuclide retarding capacity of the geologic media, a major determinant of the isolation effectiveness, was not varied as a parameter but was held constant for a particular reference site. This analysis is limited to looking only at engineered barriers whose net effect is either to delay groundwater contact with the waste form or to limit the rate of release of radionuclides into the groundwater once contact has occurred. The analysis considers only leach incident scenarios, including a water well intrusion into the groundwater near a repository, but does not consider other human intrusion events or catastrophic events. The analysis has so far been applied to a reference salt site repository system and conclusions are presented.Basically, in nearly all cases, the regional geology is the most effective barrier to release of radionuclides to the biosphere; however, for long-lived isotopes of carbon, technetium and iodine, which were poorly sorbed on the geologic media, the geology is not very effective once a leach incident is initiated

232

Mine-Tunnel Design & Monitoring Analysis for Major Faults and Complex Geological Conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Mining operations at Nanyang-Slope Coal Mine are considerably challenging. The Nanyang- Slope Coal Field has a complex tectonic structure; having major faults, large fissures and fracture- zones, and great changes in coal-seam thickness. Mine tunnel-way 301 traverses multiple complex faults with developed fractures, broken surrounding rock, and high tectonic stresses. The original rectangular-section tunnel design using anchor-bolt-mesh retainment was prone to rib-spalling, and the problem could not be controlled by use of additional encryption anchors on the tunnel sides. The mud-rock above the tunnel-ceiling is soft and argillized, which expands and softens on contact with water. This caused problems with the epoxy bonding agent failing to effectively secure bolt-anchors to the rock, resulting in anchor-bolt-mesh failure. In consideration of the complex geological conditions, a tunnel construction utilizing a curved wall arch-section and anchor-bolt- mesh-concrete spray was proposed. MJ-40 anchor-rod dynamometers were used to measure the forces in the tunnel rock-anchor bolts; and tunnel-rock deformation and surface displacement was monitored over the course of several weeks using a measuring station. Results show that the construction design effectively lowers the effects of the tectonic stresses on any one part of the tunnel, and demonstrates the safety and reliability of the tunnel-retainment and support design.

Xiang-dong ZHANG

2013-01-01

233

Study on the development of geological environmental model  

International Nuclear Information System (INIS)

The safety performance assessment was carried out in potential geological environment in the conventional research and development of geological disposal, but the importance of safety assessment based on the repository design and scenario considering the concrete geological environment will increase in the future. The research considering the link of the major three fields of geological disposal, investigation of geological environment, repository design, and safety performance assessment, is the contemporary worldwide research theme. Hence it is important to organize information flow that contains the series of information process form the data production to analysis in the three fields, and to systemize the knowledge base that unifies the information flow hierarchically. The purpose of the research is to support the development of the unified analysis system for geological disposal. The development technology for geological environmental model studied for the second progress report by JNC are organized and examined for the purpose of developing database system with considering the suitability for the deep underground research facility. The geological environmental investigation technology and building methodology for geological structure and hydro geological structure models are organized and systemized. Furthermore, the quality assurance methods in building geological environment models are examined. Information which is used and stored in the unified analysis system are examined to design database structure of the system based on the organized methodology for building geological environmental model. The graphic processing function for data stored in the unified database are examined. furthermore, future research subjects for the development of detail models for geological disposal are surveyed to organize safety performance system. (author)

234

Geological and Structural Inferences from Satellite Images in Parts of Deccan basalt covered regions of Central India  

Science.gov (United States)

In search of new areas for hydrocarbon exploration, integrated ground geophysical studies have been taken up in Central India with seismic, magnetotellurics, deep resistivity and gravity surveys. Since the region is covered with basalt and well known for its intensive tectonic activity, remote sensing method seems to have value addition to the subsurface information derived from geophysical, geological and tectonic studies. The Narmada and Tapti rift zone and Deccan basalt covered regions of Central India, stems from its complexity. A Resourcesat-1 (IRS- P6) LISS-III satellite images covering an area of approximately 250,000 sq. km corresponding to the region in and around Baroda(Vadodara), Indore, Nandurbar, Khandwa, Akot, Nasik, Aurangabad, Pune and Latur in Central India was digitally processed and interpreted to present a schematic map of the geology and elucidate the structural fabric of the region. From our study, the disposition of the intensive dyke system, various faults and other lineaments in the region are delineated. Ground truth studies have shown good correlation with lineaments/dykes indicated in remote sensing studies and have revealed distinct ENE-WSW trending lineaments, dykes which are more prominent near the Narmada and Tapti river course. Evolution of these features with Deccan volcanism is discussed with available geochronological data set. These findings are significant in relation to structural data and form a part of the geo-structural database for ground surveys.

Harinarayana, Tirumalachetty; Borra, Veeraiah; Basava, Sharana; Suryabali, Singh

235

Risk analysis and prospective geology in matters of underground storage of the nuclear industrial wastes  

International Nuclear Information System (INIS)

The principal choice concerning the radioactive waste management is to bury it in geological formations. To substantiate the validity of this choice and to persuade the public opinion of it, we must assess the risks the future populations may run. It is, therefore, necessary to foresee the behaviour and the interactions of three types of surroundings: 1. the wastes, their packaging and wrappings; 2. the geological system of confinements; 3. the external environment. A review is given of the hypothesis and methods of forecasting used or considered in this field, with a special emphasis on the prospective geology and the probabilistic approaches. (AF)

236

Cluster analysis of track structure  

International Nuclear Information System (INIS)

One of the possibilities of classifying track structures is application of conventional partition techniques of analysis of multidimensional data to the track structure. Using these cluster algorithms this paper attempts to find characteristics of radiation reflecting the spatial distribution of ionizations in the primary particle track. An absolute frequency distribution of clusters of ionizations giving the mean number of clusters produced by radiation per unit of deposited energy can serve as this characteristic. General computation techniques used as well as methods of calculations of distributions of clusters for different radiations are discussed. 8 refs.; 5 figs

237

Structural Analysis of Complex Networks  

CERN Document Server

Filling a gap in literature, this self-contained book presents theoretical and application-oriented results that allow for a structural exploration of complex networks. The work focuses not only on classical graph-theoretic methods, but also demonstrates the usefulness of structural graph theory as a tool for solving interdisciplinary problems. Applications to biology, chemistry, linguistics, and data analysis are emphasized. The book is suitable for a broad, interdisciplinary readership of researchers, practitioners, and graduate students in discrete mathematics, statistics, computer science,

Dehmer, Matthias

2011-01-01

238

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

International Nuclear Information System (INIS)

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

239

Digital filtering/enhancement/analysis of geologic long-range inclined asdic acoustic imagery  

Science.gov (United States)

Various digital filters, edge detectors, histogram modification, and three-dimensional display experiments are performed on mosaicked Geologic LOng-Range Inclined Asdic (GLORIA) acoustic imagery. These experiments have the motivation of establishing Navy capability for viewing the seafloor-especially in deep water and in three dimensions, detecting objects on the seafloor, and enhancing existing monochrome GLORIA imagery. It was found that a Gaussian filter with a kernel size of 5x 5 provided subjective enhancement to the lower intensity areas while some of the other filtering techniques, e.g., difference and gradient destroyed the dynamic range of the image. Kernel sizes were found to be extremely crucial in the experiments with this imagery, especially the median filter which did provide excellent smoothing of the imagery without sacrificing the edges. The digital mosaicking performed on this particular data set of acoustic imagery was determined to introduce multiple artificial artifacts. Image analysis showed the intensities (8 bit, 0-255)to follow the classic Gaussian distribution. Histogram equalization yielded exceptional results for adding contrast (which allows the determination ofgeologicalboundaries and detection of various seafloor objects. The vector intensity profile of the intensity offered an interesting future research objective, the correlation of acoustic imagery to bathymetry, the measurement of the depth of large bodies of water.

Shaw, Kevin B.

1990-06-01

240

Safety analysis of engineered barrier in geologic disposal of high-level waste, (1)  

International Nuclear Information System (INIS)

This reports represents analysis conditions for performance assessment of engineered barrier system of geologic disposal. The conditions for both far field and near field were analyzed by appropriate simulation models and the main results are as follows. 1) Far field conditions: By considering the initial stress state in rock formation and the mechanical stability of the disposal tunnel, the repository were assumed to be located at 500 m in depth. The application of the NATM drilling method can be possible if the rock axial compressibility is more than 250 kg/cm2. 2) Near filed conditions: Assuming glass solidified waste, dimensions of overpack and disposal pit filled with buffer material were critically determined through analyses of corrosion life, groundwater flow, temperature distribution, and radiation filed. 3) Dominant nuclides: The nuclides to be determined were selected by a simple analytical migration model in far field. The model took into account sorption effect of medium and the results were converted to the relative hazard by accounting ALI values. The maximum hazard for each nuclide under pesimistic condition (instantaneous discharge, less sorption) indicates the followings are dominant; 99-Tc, 126-Sn, 79-Se, 93-Zr, 135-Cs for FP and 241-Am, 243-Am, 239-Pu, 240-Pu, 242-Pu, 237-Np, 245-Cm, 246-Cm for TRU. (author)

 
 
 
 
241

Simultaneous determination of the noble metals in geological material by radiochemical neutron-activation analysis  

International Nuclear Information System (INIS)

A simple procedure is described for determining the noble metals in geological samples rich in chromium and copper. Powdered rock samples (0.1 to 0.3 g) are irradiated in an epithermal neutron flux, under a cadmium filter, to reduce interference from 51Cr and 64Cu. After digestion with a peroxide fusion, the noble metals are separated on Srafion NMRR ion-exchange resin. Activity from chromium(VI), retained on the resin, is eliminated by reduction to chromium(III) with iron(II) sulphate before separation. The gamma-ray activity is measured with a lithium-drifted germanium detector for palladium (109Pd), platinum (199Au), iridium (194Ir) and gold (198Au). The separation yield (iridium 40%, palladium 80%, gold 90%) is determined for each sample by irradiating the resin to activate a stable noble metal carrier. Multi-element noble metal standards (0.1 to 8 ?g) are prepared from dilute solutions (100 ?l) evaporated on resin (1 ml). The practical detection limits are 2.5 ng of palladium and platinum, 0.1 ng of iridium and 0.01 ng of gold. The reliability of the procedure was confirmed by analysing sulphide standards (PTM, PTC) and standard rocks (PCC-1, DTS-1). The method has been applied to the analysis of chrome-spinels. (author)

242

Paleoliquefaction studies in continental setting; geologic and geotechnical factors in interpretations and back-analysis  

Science.gov (United States)

Paleoliquefaction research in the last 15 years has greatly improved our ability to interpret the paleoseismic record throughout some large geographic areas, especially in regions of infrequent large earthquakes. Paleoliquefaction studies have been used extensively in the central and eastern U.S. to assess seismic hazards, and could be used elsewhere to good purpose because paleoliquefaction studies in some field settings can reveal more than other methods, such as fault studies, about the prehistoric strength of shaking and earthquake magnitude. We present guidelines for the conduct of a paleoliquefaction study in continental deposits, mainly in terms of the geologic/seismologic setting and geotechnical properties, because a successful interpretation requires factors from all these disciplines. No single discipline suffices alone. Their interactions must be appreciated in order to understand why seismically induced liquefaction features are found in some locales and not in others. The guidelines that we present also relate to three primary issues for which liquefaction features are especially useful for interpretations: Where was the tectonic source? What was the strength of shaking? And what was the magnitude? In discussing these issues we focus on the following aspects of level-ground liquefaction: (1) mechanisms that form seismic liquefaction features in the field; (2) field settings where liquefaction features should be present if strong seismic shaking has occurred; (3) field settings where an absence of liquefaction features indicates an absence of strong seismic shaking; (4) how liquefaction features should be used to interpret the tectonic source locale of a paleo-earthquake; and (5) how effects of liquefaction can be used to back-calculate the strength of shaking as well as earthquake magnitude. Several methods are available to back-calculate the strength of shaking and earthquake magnitude, and the most commonly used methods are presented and critiqued. Our critique of these methods points out the uncertainties attending each. Paleoliquefaction/paleoseismic case histories are presented to illustrate potential uncertainties in back-calculations and procedures to overcome these uncertainties. Reasonable confidence in paleoseismic interpretation generally requires using multiple methods of back-analysis, and achieving similar results from each method. An alternate approach can be used for paleo-earthquakes that were large enough to have caused liquefaction in a variety of geologic settings, in which there were differing factors affecting surface ground motions and liquefaction susceptibility. For this situation, a method such as the cyclic-stress method can be used to make back-calculations that can be cross-checked with results from other settings.

Obermeier, Stephen F.; Pond, Eric C.; Olson, Scott M.; Green, Russell A.; Stark, Timothy D.; Mitchell, James K.

2001-01-01

243

Delineation of major geologic structures in Turkey using SIR-B data  

Science.gov (United States)

Shuttle Imaging Radar-B (SIR-B) images of well mapped segments of major faults, such as the North Anatolian Fault (NAF) and East Anatolian Fault (EAF) will be studied to identify the prominent signatures that characterize the fault zones for those specific regions. The information will be used to delineate the unmapped fault zones in areas with similar geological and geomorphological properties. The data obtained from SIR-B images will be compared and correlated with the LANDSAT thematic mapper and seismicity alignments based on well constrained earthquake epicenters.

Toksoz, M. N.; Pettengill, G. H.; Ford, P.; Gulen, L.

1984-01-01

244

Environmental geologic analysis of Rio de las Taguas basin Department of Iglesia San Juan, Argentina  

International Nuclear Information System (INIS)

In this work has been stablished a relation betwwen geological units and mineralizations related with the aim to understand the hydrochemistry in this area for future environmental impact projects measurement

245

Structural Analysis of Plate Based Tensegrity Structures  

DEFF Research Database (Denmark)

Plate tensegrity structures combine tension cables with a cross laminated timber plate and can then form e.g. a roof structure. The topology of plate tensegrity structures is investigated through a parametric investigation. Plate tensegrity structures are investigated, and a method for determination of the structures pre-stresses is used. A parametric investigation is performed to determine a more optimized form of the plate based tensegrity structure. Conclusions of the use of plate based tensegrity in civil engineering and further research areas are discussed.

Hald, Frederik; Kirkegaard, Poul Henning

2013-01-01

246

Analysis of scenario development methods and practice of high level radioactive waste geological disposal  

International Nuclear Information System (INIS)

The scenario development is the key step in HLW geological disposal. The features, events and processes (FEPs) should be first considered. The FEPs can be sorted and grouped to form scenario. It is very useful and have reference value for the developing the FEPs of HLW geological disposal in a conceptual and planning stage in China by introducing the FEPs established and sorted methods. (authors)

247

Geological structure of Osaka basin and characteristic distributions of structural damage caused by earthquake; Osaka bonchi kozo to shingai tokusei  

Energy Technology Data Exchange (ETDEWEB)

The paper investigates relations between the damage caused by the Hyogo-ken Nanbu earthquake and the deep underground structures. A characteristic of the earthquake damage distribution is that the damage concentrated near faults. Most of the damages were seen on the side of faults` relatively falling rather than right above the faults and of their slightly slanting to the seaside. Distribution like this seems to be closely related to underground structures. Therefore, a distribution map of the depth of basement granite in Osaka sedimentary basin was drawn, referring to the data on basement rock depth obtained from the distribution map of gravity anomaly and the result of the survey using the air gun reflection method. Moreover, cubic underground structures were determined by 3-D gravity analysis. The result was concluded as follows: when observing the M7 zone of the low land, in particular, where the damage was great from an aspect of gravity anomaly, the basement rock below the zone declined near the cliff toward the sea, which indicates a great possibility of its being a fault. There is a high possibility that the zone suffered mostly from the damage caused by focusing by refraction and total reflection of seismic wave rays. 3 refs., 8 figs.

Nakagawa, K.; Shiono, K.; Inoue, N.; Senda, S. [Osaka City University, Osaka (JP. Faculty of Science); Ryoki, K. [Osaka Polytechnic Collage, Osaka (Japan); Shichi, R. [Nagoya University, Nagoya (Japan). Faculty of Science

1996-05-01

248

Geological aspects of radon risk  

International Nuclear Information System (INIS)

Geological factors like geochemistry, structural geology and soil physics controlling radon risk are discussed. A model for estimation of radon risk is proposed and examples from Germany are given. (orig.)

249

Preliminary analysis on the disposal of high-level radioactive wastes in geological formations of Sao Paulo state, Brazil  

International Nuclear Information System (INIS)

Several studies show that deep geological formations are the most promising solution - technical and economical - for the safe disposal of the high-level radioactive wastes produced by the nuclear industry. In order to obtain the necessary information to assess on the use of geological sites in Brazil - for the disposal of high-level radioactive waste generated by the brazilian nuclear industry - a careful survey on the basalt and granite rocks of Sao Paulo State was made. The data obtained were evaluated according to guidelines established by the International Atomic Energy Agency. The favourable and unfavourable characteristics of the basalts, granites and their respective occurrence areas in the Sao Paulo state territory - as potential waste disposal sites - were analysed. This preliminary and regional characterization is not a conclusive study whether these two rocks types are definitively the most suitable geological formations for use as nuclear waste repository or not. It is the subsidy for a more detailed analysis. Other factors such as social, political and economical aspects, ecological effects, engineering geology, heat generation rate of the waste, type of radiation emitted and corrosive nature of the waste must also be taken into account. (author)

250

High-heat geodynamic setting during the Palaeozoic evolution of the Mount Painter Province, SA, Australia: evidence from combined field structural geology and potential-field inversions  

Science.gov (United States)

A method for subsurface recognition of blind geological bodies is presented using combined surface constraints and 3-D structural modelling that incorporates constraints from detailed mapping, and potential-field inversion modelling. This method is applied to the Mount Painter Province and demonstrates that addition of low density material is required to reconcile the gravity signature of the region. This method may be an effective way to construct 3-D models in regions of excellent structural control, and can be used to assess the validity of surface structures with 3-D architecture. Combined geological and potential-field constrained inversion modelling of the Mount Painter Province was conducted to assess the validity of the geological models of the region. Magnetic susceptibility constrained stochastic property inversions indicates that the northeast to southwest structural trend of the relatively magnetic meta-sedimentary rocks of the Radium Creek Group in the Mount Painter Inlier is reconcilable with the similar, northeast to southwest trending positive magnetic anomalies in the region. Radium Creek Group packages are the major contributor of the total magnetic response of the region. However field mapping and the results of initial density constrained stochastic property inversion modelling do not correlate with a large residual negative gravity anomaly central to the region. Further density constrained inversion modelling indicates that an additional large body of relatively low density material is needed within the model space to account for this negative density anomaly. Through sensitivity analysis of multiple geometrical and varied potential-field property inversions, the best-fitting model records a reduction in gravity rms misfit from 21.9 to 1.69 mGal, representing a reduction from 56 to 4.5 per cent in respect to the total dynamic range of 37.5 mGal of the residual anomaly. This best-fitting model incorporates a volumetrically significant source body of interpreted felsic, low density material (1012 m3) impinging on the central-west of the Mount Painter Inlier and overlying Neoproterozoic sequences, and the emplacement of more mafic affinities in the northeast and east. The spatial association and circular geometry of these granitoid bodies suggests an affinity with the Palaeozoic ˜460-440 Ma British Empire Granite that outcrops in the Mount Painter Inlier. The intrusion of this additional material in the Palaeozoic could either be the product of; or contributed to, an increased local geotherm and heat flow in the region during the Palaeozoic.

Armit, R. J.; Ailleres, L.; Betts, P. G.; Schaefer, B. F.; Blaikie, T. N.

2014-10-01

251

Methodology for the biosphere analysis in the evaluation of deep geological repositories for high radioactive waste  

International Nuclear Information System (INIS)

This report summarizes the work done and the achievements reached within the R and D Project that IMA/CIEMAT has had with ENRESA during 1993-1995. The overal R and D Project has a wide radiological protection context, but the work reported here relates only to the development of a Methodology for considering the Biosphere sub-system in the assessments of deep geological repositories for high radioactive wastes (HLW). The main areas concerned within the Methodology have to do with Biosphere structure and morphology in the long-term relevant to deep disposal of HLW: in the contexts of the assessment of these systems, and appropiate modelling of the behaviour of radionuclides released to the biosphere system and with the associated human exposure. This document first provides a review of the past and present international and national concerns about the biosphere modelling and its importance in relation to the definition of safety criteria. A joint ENRESA/ANDRA/IPSN/CIEMAT study about the definition and proactical descriptions of the biosphere systems under different climatic states is then summarized. The Methodology developed by IMA/CIEMAT is outlined with an illustration of the way it works. Different steps and procedures are included for a better proactical understanding of the software tools developed within the project to support the application of the Methologoy. This Methodology is widely based on an international working group on Reference Biospheres part national work for ENRESA has been supported under a collaborative agreement with QuantiSci Ltd. Specific software development have been carried out in collaboration with QuantiSci Ltd and with the Polytechnical University of Madrid. Most of the items included within the Methodology and moreover the Methodology as a whole, follows a continuos progressive development. It is increasinaly recognized that assessment capabilities, establisment of safety criteria and regulatory framework and the steps in a regulatory development programme should all proceed in parallel. (Author)

252

Capabilities of LIBS for analysis of geological samples at stand-off distances in a Mars atmosphere  

Energy Technology Data Exchange (ETDEWEB)

The use of LIBS for stand-off elemental analysis of geological and other samples in a simulated Mars atmosphere is being evaluated. Analytical capabilities, matrix effects, and other factors effecting analysis are being determined. Through funding from NASA's Mars Instrument Development Program (MIDP), we have been evaluating the use of LIBS for future use on landers and rovers to Mars. Of particular interest is the use of LIBS for stand-off measurements of geological samples up to 20 meters from the instrument. Very preliminary work on such remote LIBS measurements based on large laboratory type equipment was carried out about a decade ago. Recent work has characterized the capabilities using more compact instrumentation and some measurements have been conducted with LIBS on a NASA rover testbed.

Cremers, D. A. (David A.); Wiens, R. C. (Roger C.); Ferris, M. J. (Monty J.); Brennetot, R. (Rene); Maurice, S. (Sylvestre)

2002-01-01

253

Geology of Brunei deltas, exploration status updated  

Energy Technology Data Exchange (ETDEWEB)

This article summarizes the petroleum geology of Negara Brunei Darussalam, the smallest but oil and gas richest country in Northwest Borneo. The paper describes the exploration history, Brunei geology, structural geology, main hydrocarbon reservoirs, seals, formation pressures, and current exploration.

Schreurs, J. [Brunei Shell Petroleum Co.Sdn. Bhd., Seria (Brunei Darussalam)

1997-08-04

254

A life cycle cost analysis framework for geologic storage of hydrogen : a user's tool.  

Energy Technology Data Exchange (ETDEWEB)

The U.S. Department of Energy (DOE) has an interest in large scale hydrogen geostorage, which could offer substantial buffer capacity to meet possible disruptions in supply or changing seasonal demands. The geostorage site options being considered are salt caverns, depleted oil/gas reservoirs, aquifers and hard rock caverns. The DOE has an interest in assessing the geological, geomechanical and economic viability for these types of geologic hydrogen storage options. This study has developed an economic analysis methodology and subsequent spreadsheet analysis to address costs entailed in developing and operating an underground geologic storage facility. This year the tool was updated specifically to (1) incorporate more site-specific model input assumptions for the wells and storage site modules, (2) develop a version that matches the general format of the HDSAM model developed and maintained by Argonne National Laboratory, and (3) incorporate specific demand scenarios illustrating the model's capability. Four general types of underground storage were analyzed: salt caverns, depleted oil/gas reservoirs, aquifers, and hard rock caverns/other custom sites. Due to the substantial lessons learned from the geological storage of natural gas already employed, these options present a potentially sizable storage option. Understanding and including these various geologic storage types in the analysis physical and economic framework will help identify what geologic option would be best suited for the storage of hydrogen. It is important to note, however, that existing natural gas options may not translate to a hydrogen system where substantial engineering obstacles may be encountered. There are only three locations worldwide that currently store hydrogen underground and they are all in salt caverns. Two locations are in the U.S. (Texas), and are managed by ConocoPhillips and Praxair (Leighty, 2007). The third is in Teeside, U.K., managed by Sabic Petrochemicals (Crotogino et al., 2008; Panfilov et al., 2006). These existing H{sub 2} facilities are quite small by natural gas storage standards. The second stage of the analysis involved providing ANL with estimated geostorage costs of hydrogen within salt caverns for various market penetrations for four representative cities (Houston, Detroit, Pittsburgh and Los Angeles). Using these demand levels, the scale and cost of hydrogen storage necessary to meet 10%, 25% and 100% of vehicle summer demands was calculated.

Kobos, Peter Holmes; Lord, Anna Snider; Borns, David James; Klise, Geoffrey T.

2011-09-01

255

Structure and geological history of the Lepanto-Cervantes releasing bend on the Abra river fault, Luzon Central Cordillera, Philippines  

Science.gov (United States)

The Luzon Central Cordillera corresponds to the uplifted and tectonized magmatic arc associated with the Manila Trench subduction zone. It is cut into N-S trending strips by the horsetail-like overprint of the Philippine strike-slip fault. The median branch, herein named the Abra River Fault, splits away to the west from the Dalton Fault and runs north-northwestward for 240 km through the range. Trending N150E in its southern part, it undergoes a sinistral bend in the Lepanto-Cervantes area, and then strikes N-S, makes a second bend and runs north-northeast up to the northwestern tip of the island. In the bend area, the compartment east of the fault has subsided, forming a narrow strip along the southern Lepanto segment and a wider trough parallel to the fault which stretches 25 km from Cervantes. The basement of the strip is position dependent, corresponding either to the Oligo-Miocene arc succession (volcanoclastic sediments and dioritic intrusive), or to the pre-Late Eocene ophiolitic basement of the arc. In the Lepanto area, two volcanic formations are preserved: the oldest one, the Malaya Formation is latest Miocene in age (6.1 ± 0.3 and 5.7 ± 0.28 Ma by K/Ar) and represents the infill of the trough, the youngest, the Mount Pudso volcanics, is Holocene in age (0.5 Ma by K/Ar). The Cervantes trough contains a thick (reaching 1700 m) volcanoclastic sequence dated as latest Miocene-Early Pliocene (3.7 ± 0.18-6.2 ± 0.28 Ma by K/Ar (the Malaya Formation). On the western and southern sides, the Abra River Fault separates the very deformed infill from the strongly uplifted pre-Late Miocene basement. On the east side, the basement, whose elevation increases gradually eastward, is disconformably overlain by the Mio-Pliocene sequence. To the north, the trough is slightly deformed. The structural analysis of the Lepanto-Cervantes strip, together with the local and regional geological and geochronological data, allow us to propose a three-stage history. The first stage during the early Late Miocene, is the major left-lateral wrench displacement of the Abra River Fault and the appearance of the bend under a transpressive regime. The second stage from latest Miocene to Early Pliocene, and marked by strong volcanic activity, comes with and/or immediately follows the subsidence of the Lepanto-Cervantes strip. The last stage, starting in the Late Pliocene, is characterized by the E-W foreshortening of the Cervantes Trough, and the beginning of its erosion.

Ringenbach, Jean Claude; Stephan, Jean François; Maleterre, Philippe; Bellon, Herve

1990-11-01

256

Geologic Mapping Exercise  

Science.gov (United States)

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

Smith, Andrew

257

Earthquakes and Geology  

Science.gov (United States)

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

Ozsvath, David

258

Structural-geological models of the Ketzin CO2 storage pilot site used for site evaluation, dynamic reservoir simulations, and monitoring purposes  

Science.gov (United States)

The saline aquifer of the Stuttgart Formation (Upper Triassic) is used for a carbon dioxide (CO2) storage research project at Ketzin, about 25 km west of Berlin (Germany). The structural and lithological site characterization relies on a comprehensive data set, consisting of former exploration data (hydrocarbon and natural gas storage exploration) and of the recent exploration, production, and monitoring data acquired at the CO2 pilot site. The quality of the data in terms of resolution and documentation is variable, covering also different scales. We present an overview of the structural and lithological characterization of the Ketzin CO2 pilot site that is based on the evolution of the geological models prepared for storage site development and site operation. In order to be able to assess risk elements, especially in the early regulatory and permitting stages of the project, the geological model building concentrated on two scales: Firstly, the site scale (called geo-model, comprising the reservoir and its overburden), and, secondly, the reservoir scale, using a higher resolution. The reservoir scale was applied to the target horizon of the CO2 storage (the Triassic Stuttgart Formation) and the Quaternary to Tertiary layers, presenting the near-surface groundwater system. The first geo-models illustrate the geological setting of the Ketzin site as a part of a salt-anticlinal structure based on seismic legacy data. These models were used to give first estimates on the deep natural groundwater flow and to establish pre-drilling profiles, but could not give reliable information on the existence and distribution of faults. Nevertheless, the estimated bed boundaries of the Stuttgart Formation served as an input for the construction of the first reservoir models of the Stuttgart Formation which were used to illustrate the expected variability and heterogeneity in rock properties. The target formation is lithologically very heterogeneous, reflecting a complex fluviatile facies distribution pattern: sandy rocks of the channel facies are embedded in muddy rocks of the floodplain facies. The facies distribution and its hydraulic parameterization were modeled using a stochastic approach. After the processing of the 3D seismic data acquired in 2005, and the drilling of three boreholes in Ketzin in 2007, the need of a re-interpretation of the geological models was given to account for the higher resolution of the new input data. In the revised models it was possible to map the main faults at the site with good accuracy. In addition, seismic facies analysis was performed by applying a spectral decomposition technique to the 3D seismic data. Thereby, subsurface features could be identified, which may indicate to some degree the distribution of the fluvial channel facies of the reservoir formation. This data was then also used to guide the stochastic reservoir modeling of the Stuttgart Formation. In addition, the interpretation of seismic CO2 monitoring data gives further evidence of the mean CO2 distribution in the subsurface and could partly guide the structural interpretation. This data enables a local deterministic refinement of the stochastic reservoir model. Finally, another well drilled into the storage formation in 2012 serves as an additional input to the geological models.

Norden, Ben; Kling, Christian; Frykman, Peter; Krawczyk, Charlotte M.

2013-04-01

259

Structural analysis of fungal cerebrosides.  

Science.gov (United States)

Of the ceramide monohexosides (CMHs), gluco- and galactosyl-ceramides are the main neutral glycosphingolipids expressed in fungal cells. Their structural determination is greatly dependent on the use of mass spectrometric techniques, including fast atom bombardment-mass spectrometry, electrospray ionization, and energy collision-induced dissociation mass spectrometry. Nuclear magnetic resonance has also been used successfully. Such a combination of techniques, combined with classical analytical separation, such as high-performance thin layer chromatography and column chromatography, has led to the structural elucidation of a great number of fungal CMHs. The structure of fungal CMH is conserved among fungal species and consists of a glucose or galactose residue attached to a ceramide moiety containing 9-methyl-4,8-sphingadienine with an amidic linkage to hydroxylated fatty acids, most commonly having 16 or 18 carbon atoms and unsaturation between C-3 and C-4. Along with their unique structural characteristics, fungal CMHs have a peculiar subcellular distribution and striking biological properties. Fungal cerebrosides were also characterized as antigenic molecules directly or indirectly involved in cell growth or differentiation in Schizophyllum commune, Cryptococcus neoformans, Pseudallescheria boydii, Candida albicans, Aspergillus nidulans, Aspergillus fumigatus, and Colletotrichum gloeosporioides. Besides classical techniques for cerebroside (CMH) analysis, we now describe new approaches, combining conventional thin layer chromatography and mass spectrometry, as well as emerging technologies for subcellular localization and distribution of glycosphingolipids by secondary ion mass spectrometry and imaging matrix-assisted laser desorption ionization time-of-flight. PMID:22164155

Barreto-Bergter, Eliana; Sassaki, Guilherme L; de Souza, Lauro M

2011-01-01

260

Structural analysis of nuclear components  

International Nuclear Information System (INIS)

THe report describes the activities accomplished in the project 'Structural Analysis Project of Nuclear Power Plant Components' during the years 1974-1982 in the Nuclear Engineering Laboratory at the Technical Research Centre of Finland. The objective of the project has been to develop Finnish expertise in structural mechanics related to nuclear engineering. The report describes the starting point of the research work, the organization of the project and the research activities on various subareas. Further the work done with computer codes is described and also the problems which the developed expertise has been applied to. Finally, the diploma works, publications and work reports, which are mainly in Finnish, are listed to give a view of the content of the project. (author)

 
 
 
 
261

‘Designerly’ Analysis of Participation Structures  

DEFF Research Database (Denmark)

With the inclusion of not only users but stake-holders of many different kinds, design processes turn into complex collaborative challenges. Thus, improving design practices requires research into how people participate and contribute in social interaction. But research methods for understand-ing such activities tend to be highly analytical and hence difficult for design researchers to engage with, if results are meant to be actionable. Through a series of experiments we develop tangible support for a ‘designerly’ interaction analysis of one important aspect of collaborative design activities: the participatory structures.

Buur, Jacob; Beuthel, Maria Rosa

262

Shakedown analysis of frame structure  

International Nuclear Information System (INIS)

In many fields of advanced technology, such as nuclear, space and aeronautic activities or off-shore exploration oil, very high requirements are imposed on structural safety and reliability. Because of the complexity of the practical loading, the response of structure to variable loading is quite different from that to the proportional load, and the failure forms are not the same. Generally there exist local failure due to plastic fatigue (alternating plasticity) and a gradual divergence of the deformed configuration (incremental collapse of ratchetting). Prager once gave the word of shakedown to a safety structure and he pointed out that an elasto-plastic structure subjected to cyclic histories of loads and/or temperature distributions is said to shake down if its plastic work is bounded. This means that the structure attains at a finite time or approaches asymptotically a situation of purely clastic cycling. When this is not the case, nonadaptation will occur. Since Melan and Koiter produced the upper and lower shakedown theorems respectively, a great achievements have been obtained in the area of theoretical and practical shakedown analysis, especially since Maier pointed out the linear program method, a lot of unsolved problems have been analyzed on the basis of shakedown theorems. In this paper, we studied the linear program formula of upper and lower bound theorem, on the basis of comparison of these two formula, a conclusion was obtained that the shakedown parameter solved by lower bound theorem is a complete solution when surplus variables arc not basic ones. Therefore it is unnecessary to solve a problem using upper bound theorem if surplus variables arc zeros when it is solved by lower bound theorem, and this easilizes somewhat what is considered

263

Use of the GIS (Geographic Information Systems in Determining Realtionship between Geology, Structures and Mineral Prospects, Southern Part of the Arabian Shield, Saudi Arabia  

Directory of Open Access Journals (Sweden)

Full Text Available GIS can be utilized in geology in different fields among them; mineral and petroleum exploration, geological mapping and reconnaissance, environmental studies, and in hydrogeological modeling. In mineral exploration the GIS is used to define a set of characteristics of specific mineral deposit that might be used as a guide to similar deposits in the region. An example is being the spatial relation of igneous intrusions and / or geological structures to the mineral prospect locations. This study aimed at using the GIS to find out the relationship of the different geological features through the layers (coverages. These features include faults, intrusions and mineral locations in the Southern Arabian Shield. Coverages (layers for the digitized material were created using ARC INFO and consequently edited, cleaned and built. Coverages were also imported and exported in order to be read by ARC VIEW. Results of study indicated an excellent association of the faults and other structures to the known mineral locations. Positive correlation can also be concluded from the spatial distribution of the mineral locations and igneous intrusions. These results may imply that igneous intrusions and structural features control mineralizations. The conclusion can help in discorving mineralizaiton in similar geological and structural setting within the Arabian Shield area.

Mustafa M. Hariri

2003-01-01

264

The seabed geomorphology and geological structure of the Firth of Lorn, western Scotland, UK  

Science.gov (United States)

We present recently collected swath bathymetry from the Firth of Lorn. 553km2 of data were collected during 2012-2013 as part of the INIS Hydro project (Ireland, Northern Ireland and Scotland Hydrographic Survey). The inshore waters covered by this survey represent a priority area for the renewable industry, shipping and tourism and encompass a number of Special Areas of Conservation (SAC) including for rocky reef habitat. Surprisingly, given this interest, this project is the first comprehensive bathymetric survey of the area. This region of near shore continental shelf is revealed as a predominantly bedrock-dominated seabed, characterised by a series of narrow, stratigraphically constrained basins eroded into the Proterozoic and Palaeozoic-age bedrock. The principal basement of the region is composed of deformed Dalradian-age metasediments overlain unconformably by ?Silurian-age Old Red Sandstones and lavas. The resistant, uneroded igneous extrusives have formed raised rock platforms. Most strikingly the central region of the Firth of Lorn is dominated by an up to 150m high vertical cliff extending for approximately 20km. The origin of this prominent feature, here termed the Insh Fault, is not well understood however it may have resulted from a combination of Dalradian-age faulting and erosion of exposed softer metasediments in the central basin. Extensive seabed faulting also occurs; possibly as Dalradian-age syn-sedimentary faults. Carboniferous and Tertiary-age minor intrusives are common throughout the region in particular the Tertiary-age dolerite dyke swarms can be traced for many kilometres, exposed on the sediment-free bedrock surfaces. The survey region includes the Corryvreckan Whirlpool and Great Race, beneath the tidal flows of which there are active submarine sand dunes. Evidence for past glaciation is widespread and well preserved in the Firth of Lorn with preserved moraines and over-deepened basins common across the area. Initial geological and geomorphological mapping shows that our understanding of the offshore outcrop geology can be greatly improved by the collection of these new high-resolution bathymetric datasets.

Howe, John; Arosio, Riccardo; Dove, Dayton; Anderton, Roger; Bradwell, Tom

2014-05-01

265

NADM Conceptual Model 1.0 -- A Conceptual Model for Geologic Map Information  

Science.gov (United States)

Executive Summary -- The NADM Data Model Design Team was established in 1999 by the North American Geologic Map Data Model Steering Committee (NADMSC) with the purpose of drafting a geologic map data model for consideration as a standard for developing interoperable geologic map-centered databases by state, provincial, and federal geological surveys. The model is designed to be a technology-neutral conceptual model that can form the basis for a web-based interchange format using evolving information technology (e.g., XML, RDF, OWL), and guide implementation of geoscience databases in a common conceptual framework. The intended purpose is to allow geologic information sharing between geologic map data providers and users, independent of local information system implementation. The model emphasizes geoscience concepts and relationships related to information presented on geologic maps. Design has been guided by an informal requirements analysis, documentation of existing databases, technology developments, and other standardization efforts in the geoscience and computer-science communities. A key aspect of the model is the notion that representation of the conceptual framework (ontology) that underlies geologic map data must be part of the model, because this framework changes with time and understanding, and varies between information providers. The top level of the model distinguishes geologic concepts, geologic representation concepts, and metadata. The geologic representation part of the model provides a framework for representing the ontology that underlies geologic map data through a controlled vocabulary, and for establishing the relationships between this vocabulary and a geologic map visualization or portrayal. Top-level geologic classes in the model are Earth material (substance), geologic unit (parts of the Earth), geologic age, geologic structure, fossil, geologic process, geologic relation, and geologic event.

2004-01-01

266

The analysis of thallium in geological materials by radiochemical neutron activation and x-ray fluorescence spectrometry: a comparison  

Energy Technology Data Exchange (ETDEWEB)

Carrier-based radiochemical neutron activation (RNAA) is a precise and accurate technique for the analysis of Tl in geological materials. For about a decade, until the mid-80s, a procedure modified from Keays et al. (1974) was used at the University of Melbourne to analyse for Tl in a wide variety of geological materials. Samples of powdered rock weighing several hundred milligrams each were irradiated in HIFAR for between 12 hours and 1 week, and subsequently fused with a sodium hydroxide - sodium peroxide mixture and several milligrams of inactive Tl carrier. Following acid digestion of the fusion mixture anion exchange resin was used to separate Tl from the major radioactive rock constituents. The Tl was then stripped from the resin and purified as thallium iodide and a yield measured gravimetrically. Activity from {sup 204}Tl (a {beta}-emitter with a 3 8 year half-life) was measured and Tl determined by reference to pure chemical standards irradiated and processed along with the unkowns. Detection limits for the longer irradiations were about one part per billion. Precision was monitored by repeat analyses of `internal standard` rocks and was estimated to be about five to ten percent (one standard deviation). On the other hand, X-ray fluorescence spectrometry (XRF) was seen as an excellent cost-effective alternative for thallium analysis in geological samples, down to 1 ppm. 6 refs. 1 tab., 1 fig.

McGoldrick, P.J.; Robinson, P. [Tasmania Univ., Sandy Bay, TAS (Australia)

1993-12-31

267

Ground subsidence geo-hazards induced by rapid urbanization: implications from InSAR observation and geological analysis  

Directory of Open Access Journals (Sweden)

Full Text Available Due to the convenient transportation and construction, cities are prone to be situated in areas with flat terrain and unstable sediments, resulting in the concurrence of ground subsidence and urbanization. Here the interaction between geology, anthropogenic processes and ground subsidence geo-hazards were investigated in the Greater Pearl River Delta region of China. Geological evidences and 2006–2010 persistent scatterer data indicate that anthropogenic activities are dominant, although the distribution of river system and Quaternary sediments are also highly related to significant displacements (primarily at a rate of ?15 to 15 mm a?1. The surface displacements derived by synthetic aperture radar interferometry suggest that the urbanization rhythm has to be routinely monitored. Considering analogous urbanization modes, particularly in developing countries, ground subsidence monitoring together with the analysis of its driving force are critical for geo-hazards early-warning, city planning as well as sustainable urbanization.

F. Chen

2012-04-01

268

Comparison of neutron activation analysis techniques for the determination of uranium concentrations in geological and environmental materials.  

Science.gov (United States)

We have described the determination of uranium in environmental, geological, and agricultural specimens by three different non-destructive nuclear methods. The effectiveness, as defined as the lower limits of detection in this work, of quantifying trace levels of bulk uranium in geological samples was evaluated for several common NAA techniques. These techniques include short-lived and medium-lived neutron activation analysis using thermal and epithermal neutrons; these results were compared with an assessment of Compton suppressed gamma-ray counting. A careful evaluation of three major (n,?) reactions with chlorine, manganese and sodium that could impede determining low levels of uranium due to high Compton continuums was done. The evaluation of Compton suppressed passive gamma counting revealed that uranium concentrations below 50 mg kg(-1) were not adequate to achieve good counting statistics using the (234m)Pa the second daughter product of (238)U. PMID:21924803

Landsberger, S; Kapsimalis, R

2013-03-01

269

Comparison of seismic sources for imaging geologic structures on the Oak Ridge Reservation, Tennessee  

International Nuclear Information System (INIS)

In this study, five non-invasive swept sources, three non-invasive impulsive sources and one invasive impulsive source were compared. Previous shallow seismic source tests (Miller and others, 1986, 1992, 1994) have established that site characteristics should be considered in determining the optimal source. These studies evaluated a number of invasive sources along with a few non-invasive impulsive sources. Several sources (particularly the high frequency vibrators) that were included in the ORR test were not available or not practical during previous tests, cited above. This study differs from previous source comparisons in that it (1) includes many swept sources, (2) is designed for a greater target depth, (3) was conducted in a very different geologic environment, and (4) generated a larger and more diverse data set (including high fold CMP sections and walkaway vertical seismic profiles) for each source. The test site is centered around test injection well HF-2, between the southern end of Waste Area Grouping 5 (WAG 5) and the High Flux Isotope Reactor (HFIR)

270

Preliminary analysis on cost estimates for high level radioactive waste geological repository  

International Nuclear Information System (INIS)

This paper briefly introduced cost estimates results and the financing system for HLW repositories in some countries. A rough cost estimate was thereafter made and some proposals regarding the finance and current investment were put forwards for China's future HLW geological repository. (authors)

271

Quantitative roughness characterization of geological surfaces and implications for radar signature analysis  

DEFF Research Database (Denmark)

Stochastic surface models are useful for analyzing in situ roughness profiles and synthetic aperture radar (SAR) images of geological terrain. In this paper, two different surface models are discussed: surfaces with a stationary random roughness (conventional model) and surfaces with a power-law roughness spectrum (fractal model). In the former case, it must be considered that for short profiles (L

Dierking, Wolfgang

1999-01-01

272

Effect of geological carbon sources on eddy covariance measurements: analysis and possible correction approaches  

Science.gov (United States)

A recent set of studies carried out in the SE of Spain highlighted the need to consider geological carbon sources when estimating the net ecosystem carbon balance (NECB) of terrestrial ecosystems located in areas potentially affected by geofluid circulation. In this study we present the mechanisms and propose a new methodology using physical parameters of the atmospheric boundary layer to quantify the CO2 coming from deep origin. To test our approach, we compare NECB estimates with seasonal patterns of soil CO2 efflux and vegetation activity measured by satellite images (NDVI) over two-year period at this site (2007/2008). According with the eddy covariance measurements the alpha grass ecosystem was a net carbon source (93.7 and 145.0 g C m-2, for the years 2007 and 2008, respectively) particularly as a result of large amounts of carbon released over the dry period. This relevant CO2 emission (reaching up to 15 umol m-2 s-1) was however not related to ecosystem activities as confirmed by measurements of soil CO2 efflux using chambers (ca. 0.5 umol m-2 s-1) and plant productivity that was minimal during this period. A simple correction based on a linear relationship between NECB and wind speed for different stability conditions and wind sectors has been used to estimate the geological flux FGEO and subtracted it from the NECB to obtain the biological flux FBIO. We then partitioned FBIO into gross primary productivity and ecosystem respiration and proved that, after removing FGEO, ecosystem and soil respiration followed similar temporal patterns. The annual contribution of the geological component to NECB was 49.6 and 46.7 % for the year 2007 and 2008, respectively. Therefore, potential contribution of geological carbon sources should be tested and quantified in those ecosystems located in areas with potential natural emission of geologic gases to the surface. References: REY A., BELELLI MARCHESINI L., WERE A., SERRANO ORTIZ P., ETIOPE G., PAPALE D, DOMINGO F., PEGORARO E. (2012). Wind as a main driver of the net ecosystem carbon balance of a semiarid Mediterranean steppe in the South East of Spain. GLOBAL CHANGE BIOLOGY, vol. 18, p. 539-554 REY A., ETIOPE G., BELELLI-MARCHESINI L., PAPALE D, VALENTINI R. (2012). Geologic carbon sources may confound ecosystem carbon balance estimates: Evidence from a semiarid steppe in the southeast of Spain. JOURNAL OF GEOPHYSICAL RESEARCH. BIOGEOSCIENCES, vol. 117 REY A., BELELLI-MARCHESINI L., ETIOPE G., PAPALE D., CANFORA E., VALENTINI R., PEGORARO E. (2013) Partitioning the net ecosystem carbon balance of a semiarid steppe into biological and geological carbon components. BIOGEOCHEMISTRY, (in review)

Papale, D.; Rey, A.; Belelli-Marchesini, L.; Etiope, G.; Pegoraro, E.

2013-12-01

273

Robustness Analysis of Kinetic Structures  

DEFF Research Database (Denmark)

The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural systems, it is of interest to investigate how robust the structures are, or what happens if a structural element is added to or removed from the original structure. The present paper discusses this issue for kinetic structures in architecture.

Kirkegaard, Poul Henning; SØrensen, John Dalsgaard

2009-01-01

274

The geological and structural evolution of the Cerro Tuzgle Quaternary stratovolcano in the back-arc region of the Central Andes, Argentina  

Science.gov (United States)

The aim of our paper is to contribute to a better knowledge of the volcanism in the back-arc region of the Central Andes and its relationships with the basement geology, the stress field and the tectonic evolution, by studying in detail the stratigraphy and the structure of the Quaternary Cerro Tuzgle stratovolcano in the Puna Plateau. Field mapping and remote sensing analysis reveal the stratigraphic architecture, the geological evolution and the volcanotectonic interactions in the Cerro Tuzgle area. For the first time in a volcano of the Puna Plateau, synthemic units bounded by unconformity surfaces have been defined, unrevealing the temporal and spatial relationships between constructive and destructive phases of the volcano history. Our study indicates that after the emplacement of a small ignimbrite deposit and of few scattered lava domes, the central Cerro Tuzgle volcano built up throughout three distinct phases of edifice construction. The first of these constructive phases ended with a previously unreported destructive event, consisting of ? 0.5 km3, catastrophic sector collapse of the volcanic edifice, whose stratigraphic position and main characteristics have been identified. The study suggests that the regional stress regime and the topography of the substrata are the main non-magmatic factors controlling the constructive and destructive phases of the volcano, including the directions of magmatic intrusions, faulting and gravitational sector failure of the volcano. The integration of synthemic stratigraphy and volcanotectonic analysis in the study of volcanic edifices showed to be an effective methodological approach for the understanding of the magmatic and tectonic evolution of the Puna Plateau.

Norini, G.; Cogliati, S.; Baez, W.; Arnosio, M.; Bustos, E.; Viramonte, J.; Groppelli, G.

2014-09-01

275

Assessment of natural radioactivity levels in rocks and their relationships with the geological structure of Johor state, Malaysia  

International Nuclear Information System (INIS)

The distribution of natural radionuclides (238U, 232Th and 40K) and their radiological hazard effect in rocks collected from the state of Johor, Malaysia were determined by gamma spectroscopy using a high-purity germanium detector. The highest values of 238U, 232Th and 40K activity concentrations (67±6, 85±7 and 722±18 Bg kg-1, respectively) were observed in the granite rock. The lowest concentrations of 238U, 232Th (2±0.1 Bq kg-1 for 238U and 2±0.1 Bq kg-1 for 232Th) were observed in gabbro rock. The lowest concentration of 40K (45±2 Bq kg-1) was detected in sandstone. The radium equivalent activity concentrations for all rock samples investigated were lower than the internationally accepted value of 370 Bq kg-1. The highest value of radium equivalent in the present study (239±17 Bq kg-1) was recorded in the area of granite belonging to an acid intrusive rock geological structure. The absorbed dose rate was found to range from 4 to 112 nGy h-1. The effective dose ranged from 5 to 138 ?Sv h-1. The internal and external hazard index values were given in results lower than unity. The purpose of this study is to provide information related to radioactivity background levels and the effects of radiation on residents in the study area under investigation. Moreover, the relationships between the radioactivity levels in the rocks within the geological structure of the studied area are discussed. (authors)

276

Construction of Subsurface Geological Structures Using a Drilling Database: A Case Study for an Intra-Arc Basin, the Osaka Plain, Southwest Japan  

Directory of Open Access Journals (Sweden)

Full Text Available Subsurface geological cross sections of 0 - 200 m depth were constructed using a dense drilling database of the Osaka Plain in the intra-arc Osaka Basin of the Japan island arc, an active plate margin. The cross sections revealed the subsurface geological structures and the geometry of folding and faulting in the basin. The comparison between the constructed subsurface cross sections and the seismic sections of the basement and basin fills at a depth of 1500 - 2000 m showed that the basement and shallow subsurface structures are similar; however, the shallow cross sections were of higher resolution than the deep seismic profiles.

Minao Sakurai

2013-04-01

277

Geologic Analysis of a Possible Oasis and Environs in the Valles Marineris, Mars  

Science.gov (United States)

We used Mars Global Surveyor data from TES, MOC, and MOLA to examine the geologic history of a region of interior layered deposits on the floor of western Candor Chasma in the Valles Marineris, Mars. This site was characterized by Geissler et al. (1993, Icarus 106) as having an unusual reddish color in multispectral images from Viking and Phobos missions. The red color was associated with two 20-km-long depressions and was thought to indicate the presence of crystalline ferric oxides (possibly hematite) in the layered deposits. Assuming that water was required to form the iron oxides via aqueous or hydrothermal alteration, these depressions may mark the site of a local oasis involving ponding or groundwater seepage in the canyon. Thermal inertia and dust index images from TES data of west Candor Chasma indicate that mantling and obscuration of local outcrops is not significant in the region of the possible oasis. To characterize the mineralogy of this area, we use multiple-endmember spectral mixture analysis (MESMA) to deconvolve TES emissivity data relative to laboratory spectra of minerals. This method identifies the minimum number of components (4 to 5) required to model the spectrum of each pixel in the spectral ranges of 307-507 cm-1 and 825-1301 cm-1 (66 TES channels) through iterative comparisons to a 33-component mineral spectral library. This library, adapted from that of ASU, includes pyroxenes, plagioclase feldspars, clays, micas, amphiboles, sulfates, carbonates, olivines, K-spar, gray hematite, and volcanic glass, plus 5 atmospheric endmembers and a blackbody. Although nanophase red hematite is undistinguished at TES wavelengths, mineral abundance maps indicate the presence of other Fe-rich minerals (such as nontronite and Fe-smectite) at this site. Gray hematite, hi-Ca clinopyroxene, Fe-rich olivine, and hi-Ca plagioclase minerals are also observed within layered deposits in the canyon walls and interior, as well as in dark materials at the base of canyon walls. These results suggest that we are mapping sites of alteration and volcanism in west Candor Chasma with the TES data. We are currently performing photoclinometric modeling of coregistered MOC (6 m/pixel) and MOLA (500 m/pixel) data via the method of Soderblom et al. (2002, LPS\\ #1254) to evaluate the orientation and possible origin of this layered deposit.

Gaddis, L. R.; Staid, M. I.; Titus, T. N.

2002-12-01

278

EFFECT OF GEOLOGICAL STRUCTURES ON THE HYDROGEOLOGICAL CHARACTERISTICS OF QUATERNARY DEPOSITS IN BARANJA  

Directory of Open Access Journals (Sweden)

Full Text Available Shifts of structural units, which started in Pliocene are specifically expressed during the Quaternary. They last still today and affected the hydrogeological relations in the region of Baranja. Lithological development is dominated by one or maximum two layers of uniform midium grained sand which in places exceeds to fine grained sand, and in some places in the sand with gravel. Mentioned structures have impacted the natural quality of groundwater. Considering individual episodes of uplift and lowering of sediments, caused by movements along a particular structures, led to changes in oxidative and reductive conditions of deposition. Consequently, different quality of water occurs in wellfields of Baranja

Maja Briški

2010-12-01

279

Preliminary spectral and geologic analysis of Landsat-4 Thematic Mapper data, Wind River Basin area, Wyoming  

Science.gov (United States)

A Landsat-4 Thematic Mapper (TM) image of the Wind River Basin area in Wyoming is currently under analysis for stratigraphic and structural mapping and for assessment of spectral and spatial characteristics using visible, near infrared, and short wavelength infrared bands. To estimate the equivalent Lambertian surface reflectance, TM radiance data were calibrated to remove atmospheric and instrumental effects. Reflectance measurements for homogeneous natural and cultural targets were acquired about one year after data acquisition. Calibration data obtained during the analysis were used to calculate new gains and offsets to improve scanner response for earth science applications. It is shown that the principal component images calculated from the TM data were the result of linear transformations of ground reflectance. In images prepared from this transform, the separation of spectral classes was independent of systematic atmospheric and instrumental factors. Several examples of the processed images are provided.

Conel, J. E.; Lang, H. R.; Paylor, E. D.; Alley, R. E.

1985-01-01

280

Large coil test structural analysis  

International Nuclear Information System (INIS)

The International Fusion Superconducting Magnet Test Facility (IFSMTF) at Oak Ridge National Laboratory (ORNL) is being utilized for testing of 2.5 x 3.5-m bore superconducting 8-T magnets produced by four international agencies (U.S., Euratom, Japan, and Switzerland). The definitive tests in the design configuration, six coils arranged in a compact torus, will begin in late 1985. Partial-array tests involving one US coil and the Japanese coil were completed in the fall of 1984. This presentation describes structural analysis using NASTRAN, with symmetry and superelement techniques, to predict the IFSMTF test stand and coil responses to various combinations of in-plane and out-of-plane loading conditions for both the partial-array and six-coil test configurations. Comparison to partial-array displacement and strain measurements are presented and discussed. Six-coil results and their utilization for determining safe levels of operation of the system are likewise discussed

 
 
 
 
281

Imaging Geological Structures Up to the Acquisition Surface Using a Hybrid Refraction-Reflection Seismic Method.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of seismic imaging is to reconstruct the reflectivity associated with subsurface structures. In standard imaging techniques, the reflectivity model usually starts a few meters below the surface, the actual depth being dependent on data acquisition parameters and the mute used to remove stretching of first arrivals after normal moveout correction. In this paper, we describe a method to image the reflectivity of near-surface structures starting from the acquisition surface. This is achi...

Mendes, Manuela; Mari, Jean-luc; Hayet, Michel

2014-01-01

282

Probabilistic structural analysis methods of hot engine structures  

Science.gov (United States)

Development of probabilistic structural analysis methods for hot engine structures is a major activity at Lewis Research Center. Recent activities have focused on extending the methods to include the combined uncertainties in several factors on structural response. This paper briefly describes recent progress on composite load spectra models, probabilistic finite element structural analysis, and probabilistic strength degradation modeling. Progress is described in terms of fundamental concepts, computer code development, and representative numerical results.

Chamis, C. C.; Hopkins, D. A.

1989-01-01

283

THE SIGNIFICANCE OF STRUCTURAL AND GEOLOGICAL RELATIONSHIP ASSESSMENT IN THE CONSTRUCTION OF THE OMBLA UNDERGROUND HYDROELECTRIC POWER PLANT  

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Full Text Available The construction design of the underground hydroelectric plant Ombla required geological and structural investigations to he carried out. Due to past earthquakes in the area permanent tectonic movements were inferred. Therefore, in the wider and adjacent surroundings of the Ombla spring it was necessary to analyze the structural fabric and the geodynamic characteristics of the area. The most active zone encountered is the front part of a thrust fault belonging to the Dinaricum regional structural unit. The compressive regime is maintained as a response to the regional stress of an approximately S-N orientation. Different displacements of various parts of the Dinaricum unit are present. Along the rim of the structural blocks, the Hum-Om-bla fault zone extends, accompanied by left transcurrent faults, Through this zone the main groundwater drainage occurs supplying the Ombla spring. In the local Ombla spring area this zone is characterized by three sub-blocks and three major faults. The most important fault for the vital facilities of the Ombla hydroelectric power plant is the Plo?ice fault which divides the structural sub-blocks. Along this fault zone there are four mutually connected. The lowest two arc active groundwater draining systems supplying the Ombla spring. The data on local stress implies the following deformation of sub-blocks: sub-blocks 2c and 2f are displaced along normal faults from 20° to 30° to the left, downwards, while the sub-block 2 d is displaced along the Plo?ice thrust fault of 100° to 130° to the left, upwards. The structural data confirmed that the building of an underground dam with a height from 100 to 130 m was feasible. The connection between the caverns and the fault zone was determined. The unfavorable position of the active Plo?ice fault zone imposes the construction of vital Ombla power plant facilities underground.

Eduard Prelogovi?

1997-12-01

284

Comparison of neutron activation analysis techniques for the determination of uranium concentrations in geological and environmental materials  

International Nuclear Information System (INIS)

We have described the determination of uranium in environmental, geological, and agricultural specimens by three different non-destructive nuclear methods. The effectiveness, as defined as the lower limits of detection in this work, of quantifying trace levels of bulk uranium in geological samples was evaluated for several common NAA techniques. These techniques include short-lived and medium-lived neutron activation analysis using thermal and epithermal neutrons; these results were compared with an assessment of Compton suppressed gamma-ray counting. A careful evaluation of three major (n,?) reactions with chlorine, manganese and sodium that could impede determining low levels of uranium due to high Compton continuums was done. The evaluation of Compton suppressed passive gamma counting revealed that uranium concentrations below 50 mg kg?1 were not adequate to achieve good counting statistics using the 234mPa the second daughter product of 238U. -- Highlights: ? Determination of uranium concentrations in geological, environmental, and agricultural specimens. ? Use of several NAA and passive counting methods. ? Identified several key interferences. ? Use of Compton suppression to minimize effects of interferences

285

Information on prospecting and analysis of the geological uraniferous favourability of Peru  

International Nuclear Information System (INIS)

The activities carried out in Peru from 1958 until 1975 in search of uranium deposits are described. In 1976 the 'Peruvian Nuclear Plan' was approved, and the Peruvian Institute of Nuclear Energy/Instituto Peruano de Energia Nuclear (IPEN) was given the responsibility of organizing and carrying out all activities related to uranium exploration and production in the country. The programme is under implementation and comprises organization of infrastructural support, training of technical personnel, selection of favourable areas, and exploration and adoption of the most favourable national policy to permit development of the national uranium resources. The criteria applied for definition of the 'uranium favourability' of the main Peruvian geological environments are described, taking into account geological composition and concepts relating to the matallogenesis and control of uranium deposits. The results of this area selection are reported. (author)

286

Application of HCMM data to regional geologic analysis for mineral and energy resource evaluation  

International Nuclear Information System (INIS)

Using a thermal-inertia mapping algorithm which provides greater discrimination capability than those in current use, a geologic feature was detected in the Cabeza Prieta, Arizona, area. Initially seen on an image formed as a difference of two thermal-inertia images, it was found to be the extension of a bilaterally symmetrical aeromagnetic feature which trends northeast for a distance of at least 1200 km

287

Mesoscopic Structure of the Punchbowl Fault, Southern California and the Geologic and Geophysical Structure of Active Strike-Slip Faults  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We examine the distribution, density, and orientation of outcrop-scale structures related to the Punchbowl Fault, an exhumed ancient trace of the San Andreas Fault, southern California, in order to determine the structure of the fault zone. The Punchbowl Fault has 44 km of right-lateral slip, and cuts the Cretaceous Pelona Schist in the study area. The mesoscopic structures examined include fractures, small faults, and veins; they were inventoried using scan lines at closely spaced stations a...

Schulz, Steven E.; Evans, James P.

2000-01-01

288

Geological Framework for the Deformation of Carbonates and Related Structures, and Their Impact on Fluid Flow  

Science.gov (United States)

The purpose of this talk is to describe mechanisms for the deformation of carbonate rocks in the upper crust and their expressions in the field. We will discuss the lithological and rheological control of the fundamental processes, as well as the structures and assemblages resulting from them. We will begin with descriptions of the fundamental structural elements, such as pressure solution seams, joints, deformation bands and the conditions that lead to their formation. These structures and their formation mechanics will then be linked to major carbonate lithologies and their petrophysical properties. Next, common structural assemblages found in deformed carbonates will be introduced. Among these will be: (1) splay pressure solution and vein pairs, (2) three orthogonal sets of pressure solution seams and, (3) a combination of paired mutually orthogonal pressure solution seams and veins. The implications of these assemblages for the conditions leading to a particular failure mode will be interpreted. Finally, the architecture of faults in carbonates will be briefly described, to include fault damage zones, fragmentation and breccia zones, and discrete dilation zones along slip surfaces, again focusing on deformation mechanisms, rheology, and diagenesis. The presentation will conclude with the idea that the deformation of carbonate rocks is more complex than most other rocks, due perhaps to the ability of carbonates to undergo dissolution under extremely shallow crustal levels. The structural products of this deformation are quite variable (in comparison to common products of deformation of other lithologies), as demonstrated by field observations from analog field sites. These conclusions have a considerable impact on mechanisms of fluid flow through deformed carbonates, which will be elaborated upon by considering field analogs. In view of the vast amount of the world's resources occurring in carbonate aquifers and reservoirs and a large number of factors affecting carbonate rock deformation, this subject should be a prime target for multidisciplinary research using all of the depositional, structural, geomechanical, petrophysical, diagenetic, hydrogeological and engineering tools and knowledge bases available.

Aydin, A.

2006-12-01

289

Soil gas 222Rn concentration in northern Germany and its relationship with geological subsurface structures  

International Nuclear Information System (INIS)

e halokinetic contribution to the 222Rn in soil gas occurrence and a possible theoretical model which summarizes the relevant processes was developed. - Highlights: ? 222Rn activity in soil gas was measured across salt structures in northern Germany. ? 222Rn activity ranges up to 105 kBq/m3 across the margins of salt structures. ? Activities caused by moraine boulder material are about 40 kBq/m3. ? We suggest that the salt dome environment has an impact on gas migration. ? A theoretical model was developed which explains the relevant processes.

290

The geologic structures observed in drillhole DOE-2 and their possible origins: Waste Isolation Pilot Plant  

International Nuclear Information System (INIS)

Questions remain as the origins of evaporite deformation within the Salado and Castile formations. Two miles north of the WIPP site, a stacked sequence of depressions was indicated by shallow boreholes. Such structures raise questions regarding the role of dissolution and gravity tectonics at the WIPP site. To investigate these structures, DOE drilled hole DOE-2 north of the WIPP site. At DOE-2, the downward displacement of stratigraphic markers in the Salado confirmed the presence of stacked depressions, which were the primary target of the drilling program. The halitic units between the marker beds were thickened compared to the average section determined from basin-wide drilling. The remaining question is whether dissolution occurred in the underlying Castile and resulted in the deformation of the Salado. Markers in the anhydrite units indicate recumbent structures and thickening of the anhydrite units by folding. As a consequence, the Castile Formation is nearly its average thickness, with the folded thickness of anhydrite compensating for the missing halite. The nearby thickening of halite within the Castile, the absence of relic anhydrite laminae in the attenuated halite units, and the high strain fabric of the remaining halite suggest that dissolution was not the dominant process in the Castile. The favored hypothesis for the Castile structures is salt flow in response to gravity inversion of the anhydrite and halite units of the Castile. 21 refs., 18 figs

291

3-D FEM modelling of geological structures caused by geometrical instabilities and contrasts in rock strength  

Science.gov (United States)

Many three-dimensional (3-D) structures in rock, which formed during the deformation of the Earth's crust and lithosphere, are controlled by a difference in mechanical strength between rock units and are often the result of a geometrical instability. Such structures are, for example, folds, pinch-and-swell structures (due to necking) or cuspate-lobate structures (mullions). These structures occur from the centimeter to the kilometer scale and the related deformation processes control the formation of, for example, fold-and-thrust belts and extensional sedimentary basins or the deformation of the basement-cover interface. The 2-D deformation processes causing these structures are relatively well studied, however, several processes during large-strain 3-D deformation are still incompletely understood. One of these 3-D processes is the lateral propagation of these structures, such as cusp propagation in a direction orthogonal to the shortening direction or neck propagation in direction orthogonal to the extension direction. We study the 3-D evolution of geometrical instabilities with numerical simulations based on the finite element method (FEM). Simulating geometrical instabilities caused by sharp variations of mechanical strength between rock units requires a numerical algorithm that can accurately resolve material interfaces for large differences in material properties (e.g. between limestone and shale) and for large deformations. Therefore, our FEM code combines a numerical contour-line technique and a deformable Lagrangian mesh with re-meshing. With this combined method it is possible to accurately follow the initial material contours with the FEM mesh and to accurately resolve the geometrical instabilities. The algorithm can simulate 3-D deformation for a visco-elasto-plastic rheology. Stresses are limited by a yield stress using a visco-plastic formulation and the viscous rheology is described by a power-law flow law. The 3-D FEM code is applied to model 3-D power-law folding and power-law Rayleigh-Taylor instabilities (diapirs) with different re-meshing scenarios. The results are tested with the analytical solution for small amplitudes and with 2-D numerical results for large amplitudes. Thereby,the small initial geometrical perturbations for folding and necking are exactly followed by the FEM mesh. In order to test and measure the numerical properties for an Eulerian mesh we use the analytical solution for a two-dimensional viscous inclusion in pure shear. The FEM code is further applied to study the evolution of lithospheric-scale 3-D slab detachment and its lateral propagation.

von Tscharner, Marina; Schmalholz, Stefan

2014-05-01

292

Geological structures and seismicity in foothills of western Taiwan and their implications of deformation in fold-and-thrust belt  

Science.gov (United States)

Characteristics of seismicity in the frontal part of an ongoing mountain-building belt can be tied to geological structural style to give some crucial information concerning the deformation of the belt. In this study, we address variation in fault plane solutions of strike-slip fault in the foothills of western Taiwan. We first describe the characteristics of structural settings on the surface in the subsurface to illustrate the differences and define the boundary between the inner and outer foothills. We then delineate variation in characteristics of seismicity in the foothills. The correspondence between the geological structure and the seismicity is demonstrated in the final. The foreland tectonics of western Taiwan can be divided into three domains: the structures of the pre-orogenic extensional tectonics, the outer part of the fold-and-thrust belt, in which low-angle thrusts mingle with high-angle reactivated normal faults, and the inner part of the belt characterized by imbricate low-angle thrusts. Pre-existing normal faults have altered the local maximum compressive stress field and trajectory of evolving thrust and strongly affected the features of the low-angle thrusts, forming orocline of the fault-and-thrust belt. The outer part of fault-and-thrust belt in northwestern Taiwan is characterized by two settings of thrust and accompanied fold, one trending ENE-WSW, representing reactivated structures of pre-existing normal faults, and the other trending NNE-SSW, parallel to the main strike of the fold-and-thrust belt. The trend of structural settings in the inner foothills is parallel to that of the fold-and-thrust belt. In the central and southern parts of western Taiwan, very few settings that trend ENE-WSW appear in the outer foothills; almost all of them remain as normal fault features. However, some of the active faults in western Taiwan may be strongly related with the reactivated normal fault, with right-lateral slip component, and occur in the frontal area of the fold-and-thrust belt or even beneath the low angle thrust. Most of the hypocenters of earthquake are located at the depth shallower than 15-20 kilometers. In the inner foothills of northwestern and central Taiwan, the resolved maximum stress axes from one set of strike-slip fault planes mainly strike NW-SE, normal to that of the fold-and-thrust belt. The orientation changes counterclockwise and then clockwise from north to south, in correspondence to the orocline of the belt. In the inner foothills of southernmost part of the study area, the resolved maximum stress axes trend obliquely at the strike of the fault-and-thrust belt. Nonetheless, one set of strike-slip fault planes are nearly parallel to the local tear faults. On the other hand, the orientation of strike-slip fault planes in the outer foothills and coastal plane strikes variably and might reflect different structural styles in different segments of the belt. Some of strike-slip fault planes might be related to the reactivated normal faults. The others might correspond to the remote stress field transmitted into the outer foothills. The coincidence between the strike of fault plane solution and that of structural setting in different parts of the foothills in northwestern Taiwan suggests that two distinct processes of mountain-building, normal fault reactivation and low angle thrusting, have been happening in different belts since the beginning of tectonics that eventually result in the structural features in the foothills today.

Yang, Kenn-Ming; Rau, Ruey-Juin; Yang, Chia-Hsun; Yang, Tzu-Ruei; Huang, Shiuh-Tsann; Mei, Wen-Wei; Wu, Jong-Chang; Tang, Yi-Jin

2013-04-01

293

The application of geological computer modelling systems to the characterisation and assessment of radioactive waste repositories  

Energy Technology Data Exchange (ETDEWEB)

The deep disposal of radioactive waste requires the collection and analysis of large amounts of geological data. These data give information on the geological and hydrogeological setting of repositories and research sites, including the geological structure and the nature of the groundwater. The collection of these data is required in order to develop an understanding of the geology and the geological evolution of sites and to provide quantitative information for performance assessments. An integrated approach to the interpretation and provision of these data is proposed in this paper, via the use of computer systems, here termed geological modelling systems. Geological modelling systems are families of software programmes which allow the incorporation of site investigation data into integrated 3D models of sub-surface geology.

White, M.J. [QuantiSci, Melton Mowbray, Leicestershire (United Kingdom); Del Olmo, C. [ENRESA, Madrid (Spain)

1996-07-01

294

Comparative analysis of the impact of geological activity on astronomical sites of the Canary Islands, Hawaii and Chile  

CERN Document Server

An analysis of the impact of seismic and volcanic activity was carried out at selected astronomical sites, namely the observatories of El Teide (Tenerife, Canary Islands), Roque de los Muchachos (La Palma, Canary Islands), Mauna Kea (Hawaii) and Paranal (Chile) and the candidate site of Cerro Ventarrones (Chile). Hazard associated to volcanic activity is low or negligible at all sites, whereas seismic hazard is very high in Chile and Hawaii. The lowest geological hazard in both seismic and volcanic activity was found at Roque de los Muchachos observatory, in the island of La Palma.

Eff-Darwich, A; Rodriguez-Losada, J A; de la Nuez, J; Hernandez-Gutierrez, L E; Romero-Ruiz, M C

2009-01-01

295

Grimsel test site: structural geology and water flow-paths in the migration shear-zone  

International Nuclear Information System (INIS)

The shear-zone in the ventilation tunnel at VT 420 at the Grimsel Test Site (GTS) is a direct continuation of the migration shear-zone AU 96 that is being used for hydraulic and tracer migration experiments. A thick drill-core (diameter 20 cm) was taken from the VT 420 location such that the fragile structures in the central fault breccia remained largely intact. After several hardening steps, thin-sections were produced for all three main deformation planes of the deformation ellipsoid (i.e. parallel/perpendicular to the cleavage and stretching lineation). Vacuum impregnation with fluorescent resin allowed the pore-space to be observed microscopically. The report contains information concerning the ductile shear-zone, brittle deformation, quantitative porosimetry, extrapolation of observed structures to larger scales, implications for water flow and transport, and suggestions for revised conceptual models. 23 figs., 5 tabs., 33 refs

296

Structural geology and mineralization of uranium deposits in the Huianpu area, west of Ordos basin  

International Nuclear Information System (INIS)

The thesis discussed the geotectonic setting of west Ordos basin, classification of structural units, fault-fold belt and structural feature of Majiatan region. Finding the stable segment in the strong structural activation region was used as the overall guidance for the uranium research and exploration, the fore-part of an over-thrust nappe belt was proposed as the favorable segment for uranium mineralization in the west of Ordos basin after several years research and exploration. Two oxidation layers of red and yellow colour was identified which the earlier oxidation was red and later oxidation alteration was yellow. The uranium ore was controlled by these two oxidation layers. The early red oxidized sandstone was experienced post-reformation such as thrust pushover, lifting, erosion and bury, block fault separation, the late yellow oxidation tended to inherit the early red oxidation and carried on the superposition modification distributed along the both wings of anticline. The thesis summarized the uranium features and metallogenic which can be used as the guidance for uranium exploration in the basin. (authors)

297

Geological events play a larger role than Pleistocene climatic fluctuations in driving the genetic structure of Quasipaa boulengeri (Anura: Dicroglossidae).  

Science.gov (United States)

Paleoclimatic and paleogeological events have been identified as being the two main drivers of genetic structuring in extant organisms. We used a montane stream-dwelling frog, Quasipaa boulengeri, to explore the relative roles played by these drivers on species in southern China, a region needing thorough studies. We detected four major matrilines, and no broadly distributed haplotypes occurred. The complex orogenesis of south-western China drove matrilineal divergence in Q. boulengeri into highly structured geographical units. These matrilines subsequently persisted in situ with stable populations rather than undergoing expansions during glacial cycling. The unification of the upper and middle Yangtze River in the Three Gorges mountain region mediated downstream colonization of this frog. Analyses identified geological events as playing a larger role than climatic fluctuations in driving the population history of Q. boulengeri. Nuclear allele analyses indicated gene flow; this maintained genetic cohesion of the species. South-eastern Sichuan Basin was identified as the area of secondary contact for several matrilines, and this area deserves further study and special protection. PMID:23216961

Yan, Fang; Zhou, Weiwei; Zhao, Haitao; Yuan, Zhiyong; Wang, Yunyu; Jiang, Ke; Jin, Jieqiong; Murphy, Robert W; Che, Jing; Zhang, Yaping

2013-02-01

298

Eye-Tracking Investigations Exploring How Students Learn Geology from Photographs and The Structural Setting of Hydrothermal Gold Deposits in the San Antonio Area, B.C.S., MX  

Science.gov (United States)

Geoscience educators commonly teach geology by projecting a photograph in front of the class. Geologic photographs often contain animals, people, and inanimate objects that help convey the scale of features in the photograph. Although scale items seem innocuous to instructors and other experts, the presence of such items is distracting and has a profound effect on student learning behavior. To evaluate how students visually interact with distracting scale items in photographs and to determine if cueing or signaling is an effective means to direct students to pertinent information, students were eye tracked while looking at geologically-rich photographs. Eye-tracking data revealed that learners primarily looked at the center of an image, focused on faces of both humans and animals if they were present, and repeatedly returned to looking at the scale item (distractor) for the duration an image was displayed. The presence of a distractor caused learners to look at less of an image than when a distractor was not present. Learners who received signaling tended to look at the distractor less, look at the geology more, and surveyed more of the photograph than learners who did not receive signaling. The San Antonio area in the southern part of the Baja California Peninsula is host to hydrothermal gold deposits. A field study, including drill-core analysis and detailed geologic mapping, was conducted to determine the types of mineralization present, the types of structures present, and the relationship between the two. This investigation revealed that two phases of mineralization have occurred in the area; the first is hydrothermal deposition of gold associated with sulfide deposits and the second is oxidation of sulfides to hematite, goethite, and jarosite. Mineralization varies as a function of depth, whereas sulfides occurring at depth, while minerals indicative of oxidation are limited to shallow depths. A structural analysis revealed that the oldest structures in the study area include low-grade to medium-grade metamorphic foliation and ductile mylonitic shear zones overprinted by brittle-ductile mylonitic fabrics, which were later overprinted by brittle deformation. Both primary and secondary mineralization in the area is restricted to the later brittle features. Alteration-bearing structures have an average NNW strike consistent with northeast-southwest-directed extension, whereas unaltered structures have an average NNE strike consistent with more recent northwest-southeast-directed extension.

Coyan, Joshua

299

Use of micro-proton elastic scattering analysis to determine water content in geological powders  

Energy Technology Data Exchange (ETDEWEB)

Hydrogen in the form of water (H{sub 2}O), hydroxyl anion (OH{sup ?}) and H{sub 2} is a pervasive component in minerals, affecting geochemical processes from the surface of the earth to its deep interior and the geophysical and rheological properties of the rock. To investigate the application of ion beam techniques to the measurement of structural water (OH{sup ?} and H{sub 2}O), purified mineral separates, volcanic glass and synthetic borosilicate glass with known total structural water contents were selected. Mineral and glass particles <50 ?m in diameter and thickness, were deposited onto Teflon filters and scanned with a focussed 2.5 MeV proton beam. Hydrogen was measured using proton elastic scattering analysis and converted to total H{sub 2}O. Heavier elements were detected via Proton-Induced X-ray Emission (PIXE). Measurements were conducted in high vacuum to detect bound water only. The water content measurements for the minerals measured showed very good agreement with bulk water measurements and literature values. This method can be used successfully to noninvasively determine the hydrogen content of individual mineral particles with >1% total water contents.

Trompetter, W.J. [Department of Ion Beam Technologies, National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt 5010 (New Zealand); Reyes, A.G. [Marine Science Department, GNS Science, 1 Fairway Drive, Avalon, Lower Hutt (New Zealand); Kennedy, J. [Department of Ion Beam Technologies, National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt 5010 (New Zealand); Markwitz, A., E-mail: a.markwitz@gns.cri.nz [Department of Ion Beam Technologies, National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt 5010 (New Zealand)

2013-07-01

300

X-ray fluorescence analysis of geological samples: exploring the effect of sample thickness on the accuracy of results  

International Nuclear Information System (INIS)

The accuracy of the simple quantitative method of elemental XRF analysis applied to thick and thin geological samples was investigated with certified reference materials. In the case of thick samples, the intensity of the calcium signal was used as a characteristic of the sample for the dark matrix correction, as it had been found to be inversely correlated with the intensity of the silicon signal. The results of the analysis of thick samples did not depend on the sample form (pressed disc or a powder in a cup), and the absorption factors were very high. In the analysis of thin samples, the detection limits, sensitivity, and accuracy have been improved, particularly for light elements. As the absorption factors are close to unity for thin samples, there is no need for a matrix-effect correction or certified reference materials

 
 
 
 
301

Determination of iridium at low levels (sub ng g-1) in geological materials by neutron activation analysis  

International Nuclear Information System (INIS)

The analysis of the platinum group elements (PGE: Ru, Rh, Pd, Os, Ir and Pt) in geological materials is difficult, due to the low concentrations of these elements (ng g-1 or sub ng g-1) and their heterogeneous distribution in many geological matrices. The determination of PGE has attracted great interest due not only to the increasing utilization of these elements in modern industry, but also to the information that these elements can provide on mantle processes. The determination of very low amounts of iridium is particularly important on account of some anomalous concentrations of iridium in sedimentary rock samples, related to the impact of an extraterrestrial object responsible for extinctions at the Cretaceous-Tertiary (K-T) boundary. In the present paper, a radiochemical neutron activation method for the determination of iridium in geological materials is presented. The procedure consisted of thermal neutron irradiation of about 500 mg of the sample, followed by sintering with sodium peroxide, precipitation with tellurium and high resolution gamma-ray spectrometry with a hyper-pure Ge detector. The accuracy and precision of the procedure were evaluated by analysis of the certified reference material SARM-7 (South Africa Bureau of Standards) and W-1 (USGS). The detection limit for the analytical conditions employed was 0.004 ng g-1. The procedure was applied to the reference materials TDB-1 and WGB-1 (CANMET), which present provisional values for Ir, and to the reference materials GXR-3, GXR-5 and GXR- 6 (USGS), which do not present information values for Ir. This work is a contribution to Ir values in these reference materials. As an example of application of the method to real samples, the developed procedure was employed in the determination of iridium in basalts from Parana basin, collected in Bom Guara do Sul, Santa Catarina, provided by the Geosciences Institute of the University of Campinas. (author)

302

Heat transfer analysis of the geologic disposal of spent fuel and high-level waste storage canisters  

International Nuclear Information System (INIS)

Near-field temperatures resulting from the storage of high-level waste canisters and spent unreprocessed fuel assembly canisters in geologic formations were determined. Preliminary design of the repository was modeled for a heat transfer computer code, HEATING5, which used the Crank-Nicolson finite difference method to evaluate transient heat transfer. The heat transfer system was evaluated with several two- and three-dimensional models which transfer heat by a combination of conduction, natural convention, and radiation. Physical properties of the materials in the model were based upon experimental values for the various geologic formations. The effects of canister spacing, fuel age, and use of an overpack were studied for the analysis of the spent fuel canisters; salt, granite, and basalt were considered as the storage media for spent fuel canisters. The effects of canister diameter and use of an overpack were studied for the analysis of the high-level waste canisters; salt was considered as the only storage media for high-level waste canisters. Results of the studies on spent fuel assembly canisters showed that the canisters could be stored in salt formations with a maximum heat loading of 134 kw/acre without exceeding the temperature limits set for salt stability. The use of an overpack had little effect on the peak canister temperatures. When the total heat load per acre decreased, the peak temperatures reached in the geologic formations decreased; however, the tlogic formations decreased; however, the time to reach the peak temperatures increased. Results of the studies on high-level waste canisters showed that an increased canister diameter will increase the canister interior temperatures considerably; at a constant areal heat loading, a 381 mm diameter canister reached almost a 500C higher temperature than a 305 mm diameter canister. An overpacked canister caused almost a 300C temperature rise in either case

303

Analysis of the geological stability of a hypothetical radioactive waste repository in a bedded salt formation  

International Nuclear Information System (INIS)

This document reports on the development of mathematical models used in preliminary studies of the long-term safety of radioactive wastes deeply buried in bedded salt formations. Two analytical approaches to estimating the geological stability of a waste repository in bedded salt are described: (a) use of probabilistic models to estimate the a priori likelihoods of release of radionuclides from the repository through certain idealized natural and anthropogenic causes, and (b) a numerical simulation of certain feedback effects of emplacement of waste materials upon ground-water access to the repository's host rocks. These models are applied to an idealized waste repository for the sake of illustration

304

Analysis of siliceous geologic materials by energy-dispersive X-ray fluorescence  

International Nuclear Information System (INIS)

The determination of the elements Al, Si, K, Ca, Ti, Cr, Mn and Fe in siliceous geologic samples by energy-dispersive X-ray fluorescence is investigated using the most adequate excitation conditions: direct excitation mode (rhodium anode X-ray tube) for the former two elements, and the secondary targets titanium for K and Ca, and germanium for Ti, Cr, Mn and Fe. For the correction of matrix effects the use of ratio methods has been tested. Procedure files have been defined allowing the automatic simultaneous acquisition and processing of spectra. (author)

305

Instrumental and radiochemical neutron activation analysis of trace iodine in geological samples  

International Nuclear Information System (INIS)

For determining trace amounts of iodine in geological samples (igneous and sedimentary rocks), applicabilities of instrumental and radiochemical neutron activation analyses (NAA) using a short-lived nuclide 128I were examined. Instrumental NAA using a TRIGA-type reactor and Cd metal or boron carbide as an absorbing filter of thermal neutron could be applied for the determination of iodine in ppm level in sedimentary rocks. Further, radiochemical NAA (RNAA) could lower the detection limit down to several ppb for igneous rock samples. Even though RNAA was employed, at least 6 samples could be routinely analyzed a day (6 h in reactor operation) using the analytical procedures reported in this work. (author)

306

Environmental geologic analysis of Rio de las Taguas basin Departmento Iglesia San Juan Argentina  

International Nuclear Information System (INIS)

A mineral environmental research project results where it has been located in Rio de las Taguas basin, Departamento Iglesia, Provincia de San Juan, Argentina. It has been placed in frontal Andean mountain in San Juan. In this geographic framework has been developed Au and Ag mineral project in order the world scale. The aim of this article is has been related the mineral and geological units bet wen the basin chemistry as well as to carry out future measurements mines impacts in this area. (author)

307

Analysis of rare earth elements on geological samples using ICP-MS  

International Nuclear Information System (INIS)

A routine method has been developed for ICP-MS determination of the REE for geological samples. Separation of REE as a group using cation exchange column has removed interferences caused by transition groups of elements and minimized the background due to complex matrix. Isobaric interferences caused by lighter REE were measured using the single pure element solutions and a correction procedure evolved. Thus using ICP-MS good quality REE data set can be acquired on rock samples with sample size not a limiting factor

308

The determination of vanadium in geological materials by activation analysis with pre-irradiation separation  

International Nuclear Information System (INIS)

Vanadium is determined in silicate rocks by neutron activation after dissolution of the samples with HF/HNO, and separation by solvent extraction. The chemical yield of the pre-irradiation separation is determined by means of 48V tracer. Results for 15 U.S. Geological Survey standard rocks are presented and discussed in relation to literature data. The method is especially useful at vanadium concentrations below 10 ppm, where purely instrumental neutron activation as well as other techniques commonly used for vanadium determinations in rocks, have inadequate sensitivity. (Auth.)

309

Structure, stratigraphy, and petroleum geology of the Little Plain basin, northwestern Hungary  

Science.gov (United States)

The basement of the Little Plain (Kisalfo??ld) basin is composed of two parts: an eastern part comprised of folded and overthrusted Triassic and Paleozoic rocks of the Pelso block (Transdanubian Central Range) compressed in the Early Cretaceous, and a western part consisting of stacked nappes of the Austroalpine zone of Paleozoic rocks, significantly metamorphosed during Cretaceous and later compression, overriding Jurassic oceanic rift-zone rocks of the Penninic zone. The evolution of the basin began in the late Karpatian-early Badenian (middle Miocene) when the eastern part of the basin began to open along conjugate sets of northeast- and northwest-trending normal faults. Neogene rocks in the study area, on the average, contain less than 0.5 wt. % total organic carbon (TOC) and, therefore, are not considered effective source rocks. Locally, however, where TOC values are as high as 3 wt. %, significant amounts of gas may have been generated and expelled. Although potential stratigraphic traps are numerous in the Neogene section, these potential traps must be downgraded because of the small amount of hydrocarbons discovered in structural traps to date. With the exception of the Cretaceous, the Mesozoic section has not been actively explored. Large anticlinal and overthrust structures involving pre-Cretaceous strata remain undrilled.

Mattick, R.E.; Teleki, P.G.; Phillips, R.L.; Clayton, J.L.; David, G.; Pogcsas, G.; Bardocz, B.; Simon, E.

1996-01-01

310

Okinawa, Japan: Geologic Battleground  

Science.gov (United States)

One of our main goals as instructors, particularly in introductory courses, is to impart students with an appreciation of how geology has influenced the course of human events. Despite the apparent accessibility of such topics, communicating this in a lively, relevant, and effective way often proves difficult. We use a series of historical events, the Pacific island hopping campaign of WWII, to engage students in an active, guided inquiry exercise to explore how terrain and the underlying geology of an area can shape historical events. Teams of students are assigned the role of planning either the defense or occupation of Okinawa Island, in the Ryukyu arc, in a theoretical version of the 1945 conflict. Students are given a package of information, including geologic and topographic maps, a list of military resources available to them at the time, and some historical background. Students also have access to "reconnaissance" images, 360o digital panoramas of the landscape of Okinawa, keyed to their maps. Each team has a week to plan their strategies and carry out additional research, which they subsequently bring to the table in the form of a written battle plan. With an instructor as arbiter, teams alternate drawing their maneuvers on a map of the island, to which the other team then responds. This continues one move at a time, until the instructor declares a victor. Throughout the exercise, the instructor guides students through analysis of each strategic decision in light of the island's structure and topography, with an emphasis on the appropriate interpretation of the maps. Students soon realize that an understanding of the island's terrain literally meant the difference between life and death for civilians and military participants alike in 1945. The karst landscape of Okinawa posed unique obstacles to both the Japanese and the American forces, including difficult landing sites, networks of natural caves, and sequences of hills aligned perpendicular to the length of the island and to American troop movement. This unique topography forced innovative tactics ranging from reverse slope defense to "blowtorch and corkscrew" offense in response. During this exercise, students apply their map-reading and interpretation skills, as well as their critical analysis abilities; the historical context, in turn, provides motivation to refine those skills. Sun Tzu wrote that all warfare is based on deception. What we hope to communicate to students with this activity is that much of warfare, and, more broadly, the way humans interact with the world, is inherently and undeniably based on geology.

Waymack, S. W.; Carrington, M. P.; Harpp, K. S.

2005-12-01

311

Structural Geology of the Active Forearc above the Maule Megathrust: Traces of a Long-lived Subduction Segment  

Science.gov (United States)

The 2010 Mw8.8 Maule earthquake rupture in central Chile produced significant upper and lower plate normal fault aftershocks including some of the largest recorded, the Mw7.0 Pichilemu events 11 days after the main event. Our understanding of the context and significance of these events for permanent deformation of the upper plate has been hampered by poorly known regional geology overlying the northern and central parts of the Maule rupture. We present new structural data of the Coastal Cordillera from the northern end of the rupture which illuminates the relationship between coseimic and long term deformation. We show that the Neogene normal faults along the outer forearc, including the Pichilemu normal fault, can be reactivated by the coseismic stress imposed within the upper plate by great subduction ruptures. The structural style of the region overlying the northern end of the Maule rupture is dominated by kilometer-scale normal faults which have been active at least throughout the Neogene. The strikes of these main structures define three structural systems: (1) a NE and (2) a NW sets of margin-oblique faults, and (3) a ~NS, margin-parallel set. The SW-dipping Pichilemu fault, which has at least three flights of uplifted marine terraces in the footwall but only a single low terrace displaying a rollover anticline in the footwall, belongs to the second group. The first two sets characterize the northernmost part of the rupture and spatially overlap, displaying a bimodal orientation; the third set occurs farther south and appears to characterize the central part of the rupture segment. Reverse faults exist but are scarce. Using the slip model of the Maule earthquake by Vigny et al. 2011 we calculate the strikes of optimally oriented normal faults along the Coastal Cordillera from the Coulomb stress increment. Comparing these strikes to the strikes of known faults and our new data, we find that nearly half agree in orientation within 22.5°. The extensional structural grain may represent the long-term signature of repeated great subduction ruptures. The northward transition from NS- to NW-trending faults outlines the northern end of a semi-elliptical pattern of major structures along the Maule rupture area, which are likely enclosing a long-lived subduction segment. The bimodal domain of NW and NE structures may represent the boundary of two adjacent segments. This suggests that great earthquakes, such Maule, have ruptured the same segment in the past and may occur in the future.

Aron, F. A.; Cembrano, J. M.; Allmendinger, R. W.; Astudillo, F.; Arancibia, G.

2012-12-01

312

The relationship of structures and geological-building of Rudòany ore field to geotechnics features  

Directory of Open Access Journals (Sweden)

Full Text Available The geostructural and geotechnical analysis was aimed at the concrete conditions of the Rudòany ore field at the Spi? region, the part of the Slovak Republic. Our research results make it possible to minimalize the negative influence of moisture liquidation of the mine field from the ecological point of view. The paper is devided into followings parts: present and future moisture liquidations and their influences on surface subsidences, the theoretical principles for the geotechnical evaluation of the subsidences and application of the principles.

Vavrek Pavol

1999-12-01

313

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

Science.gov (United States)

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

314

Features of geological structure of the southwest part of the Dushanbe trough based on data of seismic exploration and suggestion for further trend for oil and gas prospecting  

Energy Technology Data Exchange (ETDEWEB)

Results are examined of seismic studies of MOV made in the southwest part of the Dushanbe trough of the Afgano-Tajik Basin. A wave field is described which was recorded on seismograms of ground observations, and geological structure of the local elevations, Khanakinskiy, Ayninskiy and Novabadskiy. Recommendations are made for further direction of work and grouping of parametric drilling and seismic exploration for further study of the deep structure of the territory.

Barkhudaryan, A.A.; Shiryayev, V.N.

1982-01-01

315

Yosemite Geology  

Science.gov (United States)

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

316

Geologic Time.  

Science.gov (United States)

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.

317

Stratigraphic-geologic structure of the Ovcharitsa River valley in the Troyanovo-North mine field  

Energy Technology Data Exchange (ETDEWEB)

The stratigraphy of the Ovcharitsa River valley is described. Four stratigraphic terraces have been identified: the first, 200-700 m wide and an average of 9 m thick, was formed by alluvial deposits. This terrace is made up of conglomerates, sands and clayey sands. The second terrace is 170-450 m wide and 2.8-3.0 m thick and made up of carbonates, schists, muscovites, gneiss, quartz, marvel, granite and metamorphic conglomerates. Individual pieces of magnetite, chlorite, molybdenite and wolframite also occur. The third and fourth terraces have similar structures: these terraces resulted from tectonic action due to volcanic activity and as a result of erosion by the Ovcharitsa River. The role of the Gradecka and Papuska Rivers, tributaries of the Ovcharitsa river is also considered. Applying Jefferson's correlation, the water potential of these rivers was deduced. 7 references.

Mitev, A.

1984-10-01

318

Structural geology of the French Peak accommodation zone, Nevada Test Site, southwestern Nevada  

International Nuclear Information System (INIS)

The French Peak accommodation zone (FPAZ) forms an east-trending bedrock structural high in the Nevada Test Site region of southwestern Nevada that formed during Cenozoic Basin and Range extension. The zone separates areas of opposing directions of tilt and downthrow on faults in the Yucca Flat and Frenchman Flat areas. Paleomagnetic data show that rocks within the accommodation zone adjacent to Yucca Flat were not strongly affected by vertical-axis rotation and thus that the transverse strikes of fault and strata formed near their present orientation. Both normal- and oblique strike-slip faulting in the FPAZ largely occurred under a normal-fault stress regime, with least principal stress oriented west-northwest. The normal and sinistral faults in the Puddle Peka segment transfers extension between the Plutonium Valley normal fault zone and the Cane Spring sinistral fault. Recognition of sinistral shear across the Puddle Peak segment allows the Frenchman Flat basin to be interpreted as an asymmetric pull-apart basin developed between the FPAZ and a zone of east-northeast-striking faults to the south that include the Rock Valley fault. The FPAZ has the potential to influence ground-water flow in the region in several ways. Fracture density and thus probably fracture conductivity is high within the FPAZ due to the abundant fault splays present. Moreover,, fractures oriented transversely to the general southward flow of ground water through Yucca Flat area are significant and have potential to laterally divert ground water. Finally, the FPAZ forms a faulted structural high whose northern and southern flanks may permit intermixing of ground waters from different aquifer levels, namely the lower carbonate, welded tuff, and alluvial aquifers. 42 refs

319

Structural geology of the French Peak accommodation zone, Nevada Test Site, southwestern Nevada  

Energy Technology Data Exchange (ETDEWEB)

The French Peak accommodation zone (FPAZ) forms an east-trending bedrock structural high in the Nevada Test Site region of southwestern Nevada that formed during Cenozoic Basin and Range extension. The zone separates areas of opposing directions of tilt and downthrow on faults in the Yucca Flat and Frenchman Flat areas. Paleomagnetic data show that rocks within the accommodation zone adjacent to Yucca Flat were not strongly affected by vertical-axis rotation and thus that the transverse strikes of fault and strata formed near their present orientation. Both normal- and oblique strike-slip faulting in the FPAZ largely occurred under a normal-fault stress regime, with least principal stress oriented west-northwest. The normal and sinistral faults in the Puddle Peka segment transfers extension between the Plutonium Valley normal fault zone and the Cane Spring sinistral fault. Recognition of sinistral shear across the Puddle Peak segment allows the Frenchman Flat basin to be interpreted as an asymmetric pull-apart basin developed between the FPAZ and a zone of east-northeast-striking faults to the south that include the Rock Valley fault. The FPAZ has the potential to influence ground-water flow in the region in several ways. Fracture density and thus probably fracture conductivity is high within the FPAZ due to the abundant fault splays present. Moreover,, fractures oriented transversely to the general southward flow of ground water through Yucca Flat area are significant and have potential to laterally divert ground water. Finally, the FPAZ forms a faulted structural high whose northern and southern flanks may permit intermixing of ground waters from different aquifer levels, namely the lower carbonate, welded tuff, and alluvial aquifers. 42 refs.

Hudson, M.R.

1997-12-31

320

Geology and structure of major uranium-bearing zones in India and their exploration  

International Nuclear Information System (INIS)

Radiogeologic, lithostratigraphic, tectonic, and crustal evolutionary considerations have enabled the recognition of three major uranium provinces in India: the Singhbhum Province in the north-east; the Rajasthan Province in the north-west; and the Madhya Pradesh Province in central India. The paper describes the salient features of the three uranium provinces, with particular emphasis on their structural set-up, magmatectonics, and the controls of uranium mineralization, and presents a few recent case histories of individual deposits (Bagjata and Turamdih in Singhbhum, and Dhabi-Dumhat in Madhya Pradesh) discovered by integrated exploration techniques. The three uranium provinces are related to major deep-seated faults: the Singhbhum Province lies at the arcuate north-east end of the deep fault of the Eastern Ghats; the Rajasthan Province parallels the great boundary fault; and the Madhya Pradesh Province aligns with the Mahanadi-Son rift system. Some of the plausible explanations for these remarkable features are: localization of uranium ore during episodes of crustal fracturing in Precambrian times; reactivation and rejuvenation of favourable basement structures; and the role of local 'hot spots' (aided by compressional and vertical tectonics) in crustal zones anomalously enriched in the heat-producing elements. Uranium exploration strategy in India during the last three decades reveals two significant trends - the application of conventional radiometric techniquesion of conventional radiometric techniques during the period 1950-65; and introduction of sophisticated methodology comprising non-radiometric geophysical techniques, emanometry, aerial and car-borne gamma-ray spectrometry, geochemical surveys, and photogeological techniques as supplements to conventional radiometry, during the period 1965-75. It is concluded that extension of such integrated exploration techniques to favourable virgin terrains in India would lead to newer and richer uranium ore discoveries. (author)

 
 
 
 
321

Structural Analysis of Steel Structures under Fire Loading  

Directory of Open Access Journals (Sweden)

Full Text Available This paper focuses on the structural analysis of a steel structure under fire loading. In this framework, the objective is to highlight the importance of the right choice of analyses to develop, and of the finite element codes able to model the resistance and stiffness reduction due to the temperature increase. In addition, the evaluation of the structural collapse under fire load of a real building is considered, paying attention to the global behavior of the structure itself. 

C. Crosti

2009-01-01

322

Data Fusion: A decision analysis tool that quantifies geological and parametric uncertainty  

International Nuclear Information System (INIS)

Engineering projects such as siting waste facilities and performing remediation are often driven by geological and hydrogeological uncertainties. Geological understanding and hydrogeological parameters such as hydraulic conductivity are needed to achieve reliable engineering design. Information form non-invasive and minimal invasive data sets offers potential for reduction in uncertainty, but a single data type does not usually meet all needs. Data Fusion uses Bayesian statistics to update prior knowledge with information from diverse data sets as the data is acquired. Prior knowledge takes the form of first principles models (e.g., groundwater flow) and spatial continuity models for heterogeneous properties. The variability of heterogeneous properties is modeled in a form motivated by statistical physics as a Markov random field. A computer reconstruction of targets of interest is produced within a quantified statistical uncertainty. The computed uncertainty provides a rational basis for identifying data gaps for assessing data worth to optimize data acquisition. Further, the computed uncertainty provides a way to determine the confidence of achieving adequate safety, margins in engineering design. Beyond design, Data Fusion provides the basis for real time computer monitoring of remediation. Working with the DOE Office of Technology (OTD), the authors have developed and patented a Data Fusion Workstation system that has been used on jobs at the Hanford, Savannah Riv used on jobs at the Hanford, Savannah River, Pantex and Fernald DOE sites. Further, applications include an army depot at Letterkenney, PA and commercial industrial sites

323

Modified chromatographic separation scheme for Sr and Nd isotope analysis in geological silicate samples  

Directory of Open Access Journals (Sweden)

Full Text Available A novel chromatographic separation technique for Sr and Nd separation from geological silicate samples was established and successfully tested for routine use in Laboratory of Radiogenic Isotopes of the Czech Geological Survey. The separation scheme is based on combination and modification of methods published in papers by Christian Pin and his co-workers. This triple column arrangement enables the isolation of pure Sr and Nd fractions (also Sm if required from bulk-rock solution in a single step during one working day. The Sr and Nd yields are high, while blank levels remain low. This procedure minimizes the acid consumption and time needed for the separation by more than half compared to the traditional ion exchange separation techniques. The calibration of the Ln.Spec columns should be periodically monitored because the elution of REEs shifts after a period of extensive use of the resin. Suitability of this technique for Sr and Nd separation from silicate rock samples was confirmed by repeated measurements of 87Sr/86Sr and 143Nd/144Nd isotopic ratios in three international reference materials BCR-1, JA-1 and JB-3.

Denkova P

2008-01-01

324

Data Fusion: A decision analysis tool that quantifies geological and parametric uncertainty  

International Nuclear Information System (INIS)

Engineering projects such as siting waste facilities and performing remediation are often driven by geological and hydrogeological uncertainties. Geological understanding and hydrogeological parameters such as hydraulic conductivity are needed to achieve reliable engineering design. Information from non-invasive and minimally invasive data sets offers potential for reduction in uncertainty, but a single data type does not usually meet all needs. Data Fusion uses Bayesian statistics to update prior knowledge with information from diverse data sets as the data is acquired. Prior knowledge takes the form of first principles models (e.g., groundwater flow) and spatial continuity models for heterogeneous properties. The variability of heterogeneous properties is modeled in a form motivated by statistical physics as a Markov random field. A computer reconstruction of targets of interest is produced within a quantified statistical uncertainty. The computed uncertainty provides a rational basis for identifying data gaps for assessing data worth to optimize data acquisition. Further, the computed uncertainty provides a way to determine the confidence of achieving adequate safety margins in engineering design. Beyond design, Data Fusion provides the basis for real time computer monitoring of remediation. Working with the DOE Office of Technology (OTD), the author has developed and patented a Data Fusion Workstation system that has been used on jobs at the Hanford, Savannah River, Pantex and Fernald DOE sites. Further applications include an army depot at Letterkenney, PA and commercial industrial sites

325

Economic analysis of hydrocarbon exploration by simulation with geological uncertainties (exploratory wells)  

International Nuclear Information System (INIS)

A model was developed to help determine the future development of hydrocarbon reserves. The uncertainties of geological parameters were incorporated into the model in an effort to provide an assessment of the distribution of total hydrocarbon discoveries that are expected to be recovered as a result of exploration activity. The economic parameters were also incorporated into the model in an effort to determine the economic worth of multiple-wells exploration activity. The first part of this study included the geological parameters in the initial field size distribution and the number of fields distribution. Dry hole data was also considered to reflect the exploration risk. The distribution of total hydrocarbon discoveries for a selected number of exploratory wells was determined. The second part of the study included the economic parameters such as the price of oil and gas and the cost of exploration, development and production. The distribution of the number of discoveries and the distribution of total hydrocarbon discoveries was compared to produce a probability distribution of the net present value of a proposed exploration program. The offshore Nova Scotia Shelf basin was chosen for testing the methodology. Several scenarios involving changes in economic parameters were shown. This methodology could help in determining future development programs for hydrocarbon reserves. The methodology can also help governments in policy making decisions regarding taxes and roya making decisions regarding taxes and royalty regimes for exploration programs

326

Rare earth elements content in geological samples from eastern desert, Egypt, determined by instrumental neutron activation analysis  

Energy Technology Data Exchange (ETDEWEB)

Twenty representative geological samples (tonalite, granodiorite, adamellite, syenogranite, rapakivi syenogranite, alkali feldspar granite and monzogranite) were collected from G. Kattar area in Eastern Desert, Egypt, for analysis by instrumental neutron activation as a sensitive nondestructive analytical tool for the determination of 14 rare earth elements (REEs) and to find out the following: (1) what information could be obtained about the REEs and distribution patterns of REEs in geological samples under investigation, (2) to estimate the accuracy, reproducibility and detection limit of the INAA method in case of the given samples. The samples were properly prepared together with standard reference material and simultaneously irradiated in a neutron flux of 7x10{sup 11} n/cm{sup 2} s in the TRIGA Mainz research reactor facilities. The gamma spectra were collected by an HPGe detector and the analysis was done by means of a computerized multichannel analyzer. The choice of the nuclear reaction, irradiation and decay times, and of the proper gamma radiation in counting are presented and discussed. The results are found to be in good agreement with certified values.

El-Taher, A., E-mail: Atef_Eltaher@hotmail.co [Physics Department, Faculty of Science, Al-Azher University, Assuit Branch 71542 Assuit (Egypt)

2010-09-15

327

Geological-economic analysis on the exploration of backup resources for depleted mines in Lujing uranium ore-field, central-southern China  

International Nuclear Information System (INIS)

With the geological-economic evaluation program for pithead heap-leaching mining uranium deposits developed by the authors and the data of column-leaching tests and the geological reserve, the geological-economic evaluation is made to the residual geological reserves of both Lujing and Huangfengling deposit, and the geological reserves of Yangjiaonao deposit of the depleted mines in Lujing uranium ore-field, central-southern China. The results of static analysis on these reserves show that the residual geological reserves of both Lujing and Huangfengling deposit belong to sub-profitable type, but the ones of Yangjiaonao deposit is profitable with 26.56% tax-before profit. 1 tU profitable type of ore from Yangjiaonao deposit can use 2.40-3.79 tU subprofitable type of ores from Lujing and Huangfengling deposit. In order to solving the problem on scarcity of backup resources of the depleted mines in Lujing uranium ore-field and using the existing sub-profitable type of geological reserves, it is suggested that the high grade of profitable type of deposits should be explored around the exhausting mines so that the production of the mines could be profitable by the pithead heap-leaching mining method with arrangement groups of both sub-profitable and profitable type of ores. (authors)

328

High Resolution/High Fidelity Seismic Imaging and Parameter Estimation for Geological Structure and Material Characterization  

Energy Technology Data Exchange (ETDEWEB)

Our proposed work on high resolution/high fidelity seismic imaging focused on three general areas: (1) development of new, more efficient, wave-equation-based propagators and imaging conditions, (2) developments towards amplitude-preserving imaging in the local angle domain, in particular, imaging methods that allow us to estimate the reflection as a function of angle at a layer boundary, and (3) studies of wave inversion for local parameter estimation. In this report we summarize the results and progress we made during the project period. The report is divided into three parts, totaling 10 chapters. The first part is on resolution analysis and its relation to directional illumination analysis. The second part, which is composed of 6 chapters, is on the main theme of our work, the true-reflection imaging. True-reflection imaging is an advanced imaging technology which aims at keeping the image amplitude proportional to the reflection strength of the local reflectors or to obtain the reflection coefficient as function of reflection-angle. There are many factors which may influence the image amplitude, such as geometrical spreading, transmission loss, path absorption, acquisition aperture effect, etc. However, we can group these into two categories: one is the propagator effect (geometric spreading, path losses); the other is the acquisition-aperture effect. We have made significant progress in both categories. We studied the effects of different terms in the true-amplitude one-way propagators, especially the terms including lateral velocity variation of the medium. We also demonstrate the improvements by optimizing the expansion coefficients in different terms. Our research also includes directional illumination analysis for both the one-way propagators and full-wave propagators. We developed the fast acquisition-aperture correction method in the local angle-domain, which is an important element in the true-reflection imaging. Other developments include the super-wide angle one-way propagator and special full-wave reverse-time migration method. Finally, we studied the theoretical basis of true-reflection imaging and bridges imaging and inversion with the theory of diffraction tomography.

Ru-Shan Wu; Xiao-Bi Xie

2008-06-08

329

Relationship between Permeability, Elastic Moduli and Pore Structure in Porous Geological Media  

Science.gov (United States)

The petrophysical properties of porous media, such as the permeability and the elastic moduli, are essentially controlled by the geometry of the pore space. Enormous amounts of research have been devoted over the past several decades to understanding and quantifying the relationship between pore structure and petrophysical properties (for example, see Zimmerman, Compressibility of Sandstones, 1991; Dullien, Porous Media: Fluid Transport and Pore Structure, 1992; Adler, Porous Media: Geometry and Transports, 1992; Mavko et al., The Rock Physics Handbook, 1998; etc.) Although much is now known in terms of general trends, bounds, etc., the state of knowledge is still such that existing theories can rarely provide accurate numerical estimates of the permeability or bulk modulus of a given rock. To a great extent the problem lies in the fact that micromechanics-based rock physics theories typically utilize idealized pore shapes such as circular, elliptical or triangular cylinders, for which analytical solutions can readily be obtained, whereas actual pores are irregular. In this talk I will describe recent work that utilizes actual pore geometries, as observed in electron micrographs, along with some scaling laws based on the pore areas and perimeters, and simple effective medium approximations, to predict the permeability and elastic moduli of porous sedimentary rocks. The hydraulic conductivity of the individual pores are estimated from the hydraulic radius approximation, which correlates the conductance with area3/perimeter2, with the proportionality constant chosen so as to make the relation exact for a circle. Kirkpatrick's effective medium approximation for networks of conductors is used to upscale the individual pore-scale hydraulic conductivities to yield the core-scale permeability. When applied to several data sets of sandstones and carbonates, with permeabilities ranging from 0.5-1500 milliDarcies, the methodology typically predicts the permeability to within a factor of two. The compressibilities of the individual pores are estimated from a scaling law based on perimeter2/area, with the proportionality constant again found from the known case of a circular tube. The individual pore compressibilities are then averaged, weighted by area, and the differential effective medium approximation is used to convert the mean pore compressibility into the macroscopic bulk modulus. This methodology has been applied to Berea and Fontainebleau sandstone, and typically predicts the bulk modulus to within about 10%.

Zimmerman, R. W.

2007-12-01

330

The regional geological and structural setting of the uraniferous granitic provinces of Southern Africa  

International Nuclear Information System (INIS)

Uranium-bearing granites, comprising both potentially economic deposits and source rocks for uranium deposits is duricrustal and sedimentary sequences, are confined chiefly to the mobile belts of Southern Africa and to the Cape granites emplaced during late Precambrian times. The direct uranium potential of the mobile belts, i.e. the Damara, Namaqua-Natal and Limpopo belts, decreases with an increase in the age of associated ensialic diastrophism. This review paper is thus mainly confined to the Damara Belt, although a brief discussion of the potential of the Namaqua Belt is presented. Aspects of the Damara Belt that are discussed in detail, with particular reference to the occurrence of uraniferous granite, include regional tectonic setting, stratigraphy, structure, metamorphism and the patterns and origin of the uranium mineralization. Initial concentrations of uranium in basement and Nosib rocks have led, through ultrametamorphism and fractionation, to uraniferous granites of both economic and sub-economic grade. These granites, in turn, have acted as source of secondary mineralization in overlying superficial calcareous and gypsiferous deposits. The Damara Belt thus provides a good example of multicyclic processes of ore formation. With regard to the uraniferous granites of Namaqualand it is concluded that the porphyroblastic gneisses and late-intrusive Concordia granites, although not of direct economic interest, represent major sources of uranium for secondary superficial deposits. Smaller bodies of late-phase differentiates associated with the Concordia granitic gneiss may themselves, however, represent potentially economically viable deposits

331

Geology of drill hole USW VH-2, and structure of Crater Flat, southwestern Nevada  

International Nuclear Information System (INIS)

A 1219 meter (4000 ft) drill hole in Crater Flat shows the absence of buried Pliocene or Quaternary volcanic rocks, and penetrates a section of Timber Mountain, Paintbrush, and the upper part of the Crater Flat Tuffs, similar to that exposed adjacent to Crater Flat. A prominent negative aeromagnetic anomaly between the drill hole and Bare Mountain is attributed to a westward thickening section of a reversely magnetized Miocene basalt. The relatively shallow depth of this basalt in the west-central part of Crater Flat indicates that no large amount of tectonic movement has occurred in approximately the last 10 m.y. Massive brecciated wedges of Paleozoic rocks are penetrated in two stratigraphic intervals in the drill hole; the older one, between the Tiva Canyon Member of the Paintbrush Tuff and the Rainier Mesa Member of the Timber Mountain Tuff, correlates with the time of maximum faulting east of Crater Flat in the Yucca Mountain area. The younger slide masses are correlated with a large slide block of probable late Miocene age exposed along the southwestern rim of Crater Flat. The structural pattern and style buried beneath central and western Crater Flat is deduced to be similar to that exposed at Yucca Mountain, but less developed. The major fault system controlling the steep east face of Bare Mountain, though probably still active, is believed to have developed mainly as a result of caldera collapse between 13 and 14 m.y. ago. Relations between faulting and four ago. Relations between faulting and four episodes of basalt eruption in the Crater Flat area strongly suggest contemporaneity of the two processes. 17 refs., 2 figs., 3 tabs

332

Timan-Pechora petroliferous province: Geological structure, scale of generation and accumulation of hydrocarbons  

Energy Technology Data Exchange (ETDEWEB)

The Timas-Pechora petroliferous province (TPP) is a marginal system of the East Europe platform and includes the Pechora plate and Pre-Ural depression. It contains alternative mobil and stable blocks which determine the tectonic and oil and gas regions for six petroliferous complexes (PGC) in the sedimentary cover. Six petroliferous regions are in TPP. The regions consists of areas as well as zones of oil and gas generation and accumulation. A wide stratigraphic and lithological spectrum (from Ordovician to Triassic) of commercial, multizone oil and gas general and accumulation is in every region in carbonate and terrigenous reservoirs with depths ranging from 500-600 m to 5 km and more. The generation potential of TPP was determined by comparative analysis of geochemical indices of humic and sapropel organic matter with simultaneous determination of catagenesis grade of rocks and organic matter. The main zones of oil generation (with lower limits 3.5-5.3 km for different PGCs) and gas generation also was determined. The areas of oil and gas generation and accumulation were separated on the basis of production-genetic indexes as well as by generation potential. Accumulative possibilities of natural reservoirs in different kinds of traps were evaluated qualitatively and quantitatively.

Belonin, M.D.; Bogatsky, V.J.; Shimansky, O.M.; Kovalenko, V.S.; Tarasov, P.P.; Yaralov, B.A.; Prischepa, O.M. (Ministry of Geology, Moscow (USSR))

1991-08-01

333

ITER vacuum vessel structural analysis  

International Nuclear Information System (INIS)

This paper summarizes analyses performed on the ITER vacuum vessel, emphasizing dynamic structural analyses with disruption loading. Current results are presented and evaluated against the ITER design criteria

334

Submarine geology of the Hilina slump and morpho-structural evolution of Kilauea volcano, Hawaii  

Science.gov (United States)

Marine geophysical data, including SEA BEAM bathymetry, HAWAII MR1 sidescan, and seismic reflection profiles, along with recent robot submersible observations and samples, were acquired over the offshore continuation of the mobile Kilauea volcano south flank. This slope comprises the three active hot spot volcanoes Mauna Loa, Kilauea, and Loihi seamount and is the locus of the Hawaiian hot spot. The south flank is the site of frequent low-intensity seismicity as well as episodic large-magnitude earthquakes. Its sub-aerial portion creeps seaward at a rate of approximately 10 cm/year. The Hilina slump is the only large submarine landslide in the Hawaiian Archipelago thought to be active, and this study is one of the first to more highly resolve submarine slide features there. The slump is classified into four distinct zones from nearshore to the island's base. Estimates of size based on these data indicate a slumped area of 2100 km 2 and a volume of 10,000-12,000 km 3, equivalent to about 10% of the entire island edifice. The overall picture gained from these data sets is one of mass wasting of the neovolcanic terrain as it builds upward and seaward, though reinforcement by young and pre-Hawaii seamounts adjacent to the pedestal is apparent. Extensive lava delta deposits are formed by hyaloclastites and detritus from recent lava flows into the sea. These deposits dominate the upper submarine slope offshore of Kilauea, with pillow breccia revealed at mid-depths. Along the lower flanks, massive outcrops of volcanically derived sedimentary rocks were found underlying Kilauea, thus necessitating a rethinking of previous models of volcanic island development. The morphologic and structural evolutionary model for Kilauea volcano and the Hilina slump proposed here attempts to incorporate this revelation. A hazard assessment for the Hilina slump is presented where it is suggested that displacement of the south flank to date has been restrained by a still developing northeast lateral submarine boundary. When it does fully mature, the south flank may be more subject to land slips triggered by large, long duration earthquakes and thus Kilauea may undergo more frequent episodes of failure with increased displacements.

Smith, John R.; Malahoff, Alexander; Shor, Alexander N.

1999-12-01

335

XAFS study and two dimensional chemical state analysis of sulfur in geological samples  

International Nuclear Information System (INIS)

The S K-edge XANES spectra were measured in X-ray fluorescent mode by the use of synchrotron radiation at BL-8B beamline, Photon Factory, Tsukuba. The S K-XANES spectra of elemental sulfur, sodium thiosulfate and copper sulfate exhibited characteristic chemical shifts, as well as unique spectral shapes. The chemical shift between sulfide and sulfate sulfur is as large as 13 eV. The spectrum of sodium thiosulfate is characterized by the distinguished two peaks at 2465 eV and 2476 eV, and are successfully attributed to S2- and S6+ in the S2O3 tetrahedral unit in the structure. On the contrary, the S K-XANES spectra of HgS(metacinnabar), PbS(galena), MnS(alabandite) and ZnS(sphalerite) indicated that the absorption-edge energies of these compounds were similar to each other and were almost equal to that of elemental sulfur. Two dimensional chemical state analysis of a sedimentary rock containing sulfur was carried out and compositional image of sulfate and sulfide ion was successfully obtained by changing the excitation energy. The result visualized the oxidation process of the rock sample by weathering. (author)

336

Correlation of the radiometric analysis with the surface geology of Wadi Fatira,. central eastern desert, egypt  

International Nuclear Information System (INIS)

Fatira area built up of a sequence of igneous and metamorphic rocks of late precambrian age. It is un conformably overlain in the western parts by Nubian sands tons mostly of cretaceous age. The radiometric studies of the geological units cropping out in the area, revealed that each rock unit has a characteristic value of activity. The younger units through the basement complex, always possess higher radioactivity relative to the older ones. As a result the emerging geosynclinal volcanics and late orogenic granites attain the highest radiometric values and they could reflect the chemical composition of rock.these studies also revealed the presence of three phases of red pink granites in the eastern desert of egypt, each of them possesses a characteristic radiometric value. This is in agreement with the field, petrographic and petrochemical characteristics of such classification

337

Geological remote sensing from space  

Energy Technology Data Exchange (ETDEWEB)

Remote sensing from space, essentially an extension of lower level, airborne remote sensing, offers many new advantages to assist in the geological and geophysical mapping of the earth. To be successfully applied, however, geological remote sensing from space must be utilized in conjunction with the other tools presently used in geological and geophysical mapping. Using space remote sensing it is now possible to specify the geological requirements for remote sensing from space. Although the geological parameters differ for deposits of the various resources and for various engineering and environmental geological problems, they are all involved in the general geological, geophysical, and geochemical mapping of the earth's surface. They include such things as structural interpretation, rock, mineral, soil, and vegetation discrimination and identification, and alteration studies. Against these geological parameters, present or potential space sensing capabilities can be compared for maximum geological utilization. In considering such capabilities, it is important to differentiate between application capabilities (e.g., those that are currently available or nearly available) and experimental capabilities (those subject to further technical development). The Geosat Workshop attempted to delineate geological parameters for oil, gas, and mineral exploration and for engineering and environmental geology. From these parameters, six major potential applications not available from current or past space technology (Landsat, and Skylab) are recognized. The geological parameters and corresponding potential Geosat capabilities are summarized.

Henderson, F.B. III; Swann, G.A. (eds.)

1976-01-01

338

Fourier Analysis and Structure Determination--Part III: X-ray Crystal Structure Analysis.  

Science.gov (United States)

Discussed is single crystal X-ray crystal structure analysis. A common link between the NMR imaging and the traditional X-ray crystal structure analysis is reported. Claims that comparisons aid in the understanding of both techniques. (MVL)

Chesick, John P.

1989-01-01

339

Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures  

Energy Technology Data Exchange (ETDEWEB)

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic gradients between aquifer types are downward throughout most of the study area; however, flow from the alluvial-volcanic aquifer into the underlying carbonate aquifer, where both aquifers are present, is believed to be minor because of an intervening confining unit. Limited exchange of water between aquifer types occurs by diffuse flow through the confining unit, by focused flow along fault planes, or by direct flow where the confining unit is locally absent. Interflow between regional aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form intermediate and regional flow systems. The implications of these flow systems in controlling transport of radionuclides away from the underground test areas at the Nevada Test Site are briefly discussed. Additionally, uncertainties in the delineation of aquifers, the development of potentiometric contours, and the identification of flow systems are identified and evaluated. Eleven tributary flow systems and three larger flow systems are mapped in the Nevada Test Site area. Flow systems within the alluvial-volcanic aquifer dominate the western half of the study area, whereas flow systems within the carbonate aquifer are most prevalent in the southeastern half of the study area. Most of the flow in the regional alluvial-volcanic aquifer that moves through the underground testing area on Pahute Mesa is discharged to the land surface at springs and seeps in Oasis Valley. Flow in the regional carbonate aquifer is internally compartmentalized by major geologic structures, primarily thrust faults, which constrain flow into separate corridors. Contaminants that reach the regional carbonate aquifer from testing areas in Yucca and Frenchman Flats flow toward downgradient discharge areas through the Alkali Flat-Furnace Creek Ranch or Ash Meadows flow systems and their tributaries.

Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

2010-01-25

340

Structural analysis of CANFLEX fuel bundles  

International Nuclear Information System (INIS)

The CANFLEX fuel bundle has been developed by KAERI/AECL jointly to facilitate the use of various fuel cycles in CANDU-6 reactor. As one of the design evaluations, the structural analysis of the fuel bundles by hydraulic drag force is performed to evaluate the the fuel integrity in the period of the refuelling in CANDU-6. The structural integrity is evaluated by FEM modelling for the complicated bundles configuration in channel. It is noted that the present analysis method is newly developed for the structural integrity evaluation. The analysis results show that the fuel bundle is shown to keep its structural integrity during the refuelling

 
 
 
 
341

Computer applications for engineering/structural analysis  

Energy Technology Data Exchange (ETDEWEB)

Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.

Zaslawsky, M.; Samaddar, S.K.

1991-01-01

342

Structural Controls of the MacFarlane Geothermal System, Humboldt County, Nevada: New Insights Based on Detailed Geologic Mapping, Shallow Temperature Surveys, and Magnetic Data  

Science.gov (United States)

Detailed geologic mapping, structural analysis, magnetic and two-meter temperature data, integrated with previous datasets, constrain the structural controls of the MacFarlane geothermal system. MacFarlane hot springs and the travertine fissure ridges lie within a relay ramp. The relay ramp is formed between two overlapping, north-northeast-striking, west-dipping Holocene normal faults exposed in Lake Lahontan sediments. Other mapped faults near the hot spring include a north-striking, west-dipping Tertiary fault east of MacFarlane hot springs. The highest temperature gradient is found at the projected intersection between the Tertiary and north-northeast-striking Quaternary fault, ˜2.5 km northeast of the hot spring (Sibbett et al., 1982; Swanberg and Bowers, 1982). Our new data suggest other controls involving the relay ramp geometry of the Holocene faults. The anomalous orientation of the travertine fissure ridge motivated this study of the structural controls of the geothermal system. MacFarlane hot spring is located on the eastern margin of the Black Rock Desert, ˜85 km west of Winnemucca, in Humboldt County, Nevada. The active hot spring emerges from the west end of an east-trending travertine fissure ridge, which is ˜180 m long. The travertine fissure ridge is up to ˜2 m tall and ˜5 m wide, and has a central fissure along its long axis. The orientation of the travertine fissure ridge indicates local north-south extension, which is inconsistent with the regional west-northwest extension of the northwestern Basin and Range province. The anomalous travertine orientation is due to fractures that occurred during formation of a relay ramp between two overlapping fault segments.

Kraushaar, Sabina M.

343

Estimating the supply and demand for deep geologic CO2 storage capacity over the course of the 21st Century: A meta-analysis of the literature  

Energy Technology Data Exchange (ETDEWEB)

Whether there is sufficient geologic CO2 storage capacity to allow CCS to play a significant role in mitigating climate change has been the subject of debate since the 1990s. This paper presents a meta- analysis of a large body of recently published literature to derive updated estimates of the global deep geologic storage resource as well as the potential demand for this geologic CO2 storage resource over the course of this century. This analysis reveals that, for greenhouse gas emissions mitigation scenarios that have end-of-century atmospheric CO2 concentrations of between 350 ppmv and 725 ppmv, the average demand for deep geologic CO2 storage over the course of this century is between 410 GtCO2 and 1,670 GtCO2. The literature summarized here suggests that -- depending on the stringency of criteria applied to calculate storage capacity – global geologic CO2 storage capacity could be: 35,300 GtCO2 of “theoretical” capacity; 13,500 GtCO2 of “effective” capacity; 3,900 GtCO2, of “practical” capacity; and 290 GtCO2 of “matched” capacity for the few regions where this narrow definition of capacity has been calculated. The cumulative demand for geologic CO2 storage is likely quite small compared to global estimates of the deep geologic CO2 storage capacity, and therefore, a “lack” of deep geologic CO2 storage capacity is unlikely to be an impediment for the commercial adoption of CCS technologies in this century.

Dooley, James J.

2013-08-05

344

Investigation of corrosion and analysis of passive films concerning some nickel alloys and stainless steels in reconstructed geological environments  

International Nuclear Information System (INIS)

This research thesis addresses the corrosion behaviour of materials which might be used for the fabrication of radioactive waste containers. After a bibliographical study on films formed on Fe-Cr-Ni alloys, this research concentrates on passivation and de-passivation phenomena of three nickel-base alloys among the most resistant to corrosion and which also meet processing and economic criteria: Hastelloy C4, Inconel 625 and ZICNDU 25-20. Titanium and Ti-Pd alloy are also studied. Parameters governing pitting corrosion are notably studied. After a recall of knowledge on passive films formed on Fe-Cr-Ni alloys, and a presentation of experimental and technical conditions, the author reports and discussed the results obtained by electrochemical studies, reports the determination of factors governing alloy passivation in geological waters. The influence of some soluble impurities is notably studied. The author reports the analysis by glow discharge optical emission spectrometry to determine the composition of passive films with respect to geological water nature, the immersion duration and the electrode potential. Additional surface analyses are performed by X-ray photoelectron spectrometry (XPS or ESCA) and secondary ion mass spectrometry (SIMS). Finally, the author uses a dosing method by neutron radio-activation of alloy elements to determine dissolution mechanisms

345

Reconstructing the geological and structural history of an active geothermal field: A case study from New Zealand  

Science.gov (United States)

The utilisation of geothermal systems benefits from an understanding of the host-rock geology, locations and controls of permeability pathways, and the nature and timing of magmatic sources providing thermal energy. Kawerau Geothermal Field in the central Taupo Volcanic Zone (TVZ) of New Zealand is currently developed for electricity generation and direct uses of high-temperature steam to ~ 200 MW electrical output. The Kawerau geothermal system is hosted in a sequence of volcanic lithologies (tuffs, lavas and intrusive bodies) and sediments that overlie faulted Mesozoic metasedimentary (greywacke) basement. Identification of lithologies in the volcanic/sedimentary sequence is challenging due to the levels of hydrothermal alteration and lithological similarities. A combination of detailed petrological investigations, consideration of the emplacement processes and greater certainty of crystallisation or eruption ages through U-Pb age determinations on zircons is used to reconstruct the depositional and faulting evolution of the rocks hosting the currently active hydrothermal system. The oldest event inferred is faulting of the greywacke along northwest-southeast orientated, dominantly strike-slip structures to generate half-grabens that were filled with sediments, incorporating two dated ignimbrites (2.38 ± 0.05 and 2.17 ± 0.05 Ma). A 1.46 ± 0.01 Ma ignimbrite was deposited relatively evenly across the field, implying that any topographic relief was subdued at that time. Subsequent deposition of ignimbrites occurred in episodes around 1.0, 0.55-0.6, and 0.32 Ma, interspersed with thin sedimentary sequences that accumulated at average rates of 0.06 mm yr- 1. Andesite lavas from a buried composite cone occur as a conformable package between units dated at 1.0 and 0.6 Ma. Bodies of coherent rhyolite occur at multiple stratigraphic levels: two magma types with associated tuffs were emplaced as domes and sills at 0.36 ± 0.03 Ma, and a third type at 0.138 ± 0.007 Ma as dikes, and domes that are exposed at surface. The andesitic Putauaki composite cone southwest of the field first erupted around 8 ka, but earlier hydrothermal eruption breccias imply that magma was intruded to shallow depths as early as ~ 16 ka. Age data and associated correlations show that post-1.5 Ma normal faulting has accompanied episodic subsidence of the Kawerau area, with fault movement focused between northeast-southwest structures (associated with the geometry of the modern TVZ) and the reactivated northwest-southeast structures associated with most displacement in the area prior to 1.5 Ma. Contrasts between emplacement of coherent rhyolite as sills at 0.36 Ma and a dike at 0.138 Ma reflect a shift in orientation of the principal stress axes in response to initiation of the modern TVZ rifting regime. Most volcanic rocks at Kawerau are distally sourced from elsewhere in the TVZ but form local marker horizons that delineate topographic relief within the field, and additionally constrain past subsidence rates. Current rates of subsidence and thermal output at Kawerau are geologically recent features associated with latest Quaternary rifting processes (< ~ 50 ka) and emplacement of the magmatic system for Putauaki volcano (~ 16 ka) respectively.

Milicich, S. D.; Wilson, C. J. N.; Bignall, G.; Pezaro, B.; Bardsley, C.

2013-07-01

346

NASA Structural Analysis System (NASTRAN)  

Science.gov (United States)

Program aids in structural design of wide range of objects, from high-impact printer parts to turbine engine blades, and fully validated. Since source code included, NASTRAN modified or enhanced for new applications.

Purves, L.

1991-01-01

347

Non-linear analysis of concrete structures  

International Nuclear Information System (INIS)

Work in progress on the inelastic analysis of concrete structures using the finite element method is described. The study serves two objectives, the working stress design and the ultimate load analysis. The distribution of temperature, of particular importance in nuclear structures, is studied. The basis for the non linear analysis of instantaneous deformations is given, based in plasticity theory. Linear and non linear viscoelasticity based in the state variables approach are studied. Several numerical examples are presented. (Author)

348

Incorporating Content Structure into Text Analysis Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Information about the content structure of a document is largely ignored by current text analysis applications such as information extraction and sentiment analysis. This stands in contrast to the linguistic intuition that rich contextual information should benefit such applications. We present a framework which combines a supervised text analysis application with the induction of latent content structure. Both of these elements are learned jointly using the EM a...

Sauper, Christina Joan; Haghighi, Aria; Barzilay, Regina

2010-01-01

349

Geochemical Impact on the Caprock Porous Structure during CO2 Geological Storage : A Laboratory and Modeling Study  

Science.gov (United States)

CO2 storage is envisioned as a technique which reduces large quantities of CO2 rejected in the atmosphere because of many human activities. The effectiveness of this technique is mainly related to the storage capacity as well as its safety. The safety of this operation is primarily based on the conservation of petro-physical properties of the caprock, which prevents the transport of CO2 towards the surface. However when CO2 reaches the reservoir/caprock interface due to buoyancy effects, the interaction between interstitial fluid and injected fluid creates a serie of dissolution/precipitation reactions affecting the properties of containment of the caprock, which is generally characterized by low transport properties. This study aims to assess the impact caused by CO2/interstitial fluid interaction on the nanostructure of a caprock under geological storage conditions. In order to do this, degradation experiments at high pressure of CO2 (88 bar) and isothermal (55°C) conditions have been conducted using batch reactors for 3.5 months. The sample used for these experiments is a well characterized shale, from the Tournemire formation (Aveyron-France). Porosity evolution has been followed by using volumetric adsorption at low pressure, from advanced NLFDT and classical theories based on the micropores filling, and capillary condensation phenomena. Results showed a slight variation in both mesopores and micropores size distributions, as a result of dissolution processes, which dominated at laboratoty time scale. Furthermore, chemical analysis from the water sampled showed an overall increase in Ca,Mg,K,Si,Na. The results obtained by physical adsorption and water chemistry analysis were consistent, with geochemical modeling, which suggested reaction paths with calcite dissolution as the main mineral, by producing porosity at short term and (clays, feldspars) dissolution of aluminosilicates dominating at long term.

Rhenals Garrido, D. R.; Lafortune, S.; Souli, H.; Dubujet, P.

2013-12-01

350

The encyclopedia of applied geology  

Energy Technology Data Exchange (ETDEWEB)

This compendium of engineering geology data includes contributions by experts from many countries. Topics center around the field of engineering geology, with special focus on landscapes, earth materials, and the ''management'' of geological processes. How to use geology to serve man is given particular attention. More than 80 entries deal with hydrology, rock structure monitoring, soil mechanics, and engineering geology. Facts are provided on earth science information and sources, electrokinetics, forensic geology, geogryology, nuclear plant siting, photogrammetry, tunnels and tunneling, urban geomorphology, and well data systems. This guide explains the geology of alluvial plains, arid lands, beaches and coasts, delataic plains, cold regions, glacial landscapes, and urban environments. Detailed analyses are given of the geotechnical properties of caliche, clay, duricrust, soil, laterite, marine sediments, and rocks.

Finkl, C.W.

1984-01-01

351

Regional gravity analysis of the crustal structure of Tunisia  

Science.gov (United States)

Gravity data were integrated with seismic refraction/reflection data, well data and geological investigations to determine a general crustal structure of Tunisia. The gravity data analysis included the construction of a complete Bouguer gravity anomaly map, residual gravity anomaly maps, horizontal gravity gradient maps and a 2.5-D gravity model. Residual gravity anomaly maps illustrate crustal anomalies associated with various structural domains within Tunisia including the Sahel Block, Saharian Flexure, Erg Oriental Basin, Algerian Anticlinorium, Gafsa Trough, Tunisian Trough, Kasserine Platform and the Tell Mountains. Gravity anomalies associated with these features are interpreted to be caused either by thickening or thinning of Palæozoic and younger sediments or by crustal thinning. Analysis of the residual gravity anomaly and horizontal gravity gradient maps also determined a number of anomalies that may be associated with previously unknown structures. A north-south trending gravity model in general indicated similar subsurface bodies as a coincident seismic model. However, thinner Mesozoic sediments within the Tunisian Trough, thinner Palæozoic sediments in the Gafsa Trough, and a greater offset on the Saharian Flexure were required by the gravity data. Additionally, basement uplifts under the Kasserine Platform and Gafsa Trough, not imaged by seismic data, were required by the gravity data. The gravity model revealed two previously unknown basins north and south of the Algerian Anticlinorium (5 km), while the Erg Oriental Basin is composed of at least two sub-basins, each with a depth of 5 km.

Jallouli, Chokri; Mickus, Kevin

2000-01-01

352

The structurally-controlled rockslide of Barmasse (Valais, Switzerland): structural geology, ground-based monitoring and displacement vs. rainfall modeling.  

Science.gov (United States)

In this communication, we show a case study on the Barmasse rockslide (Val de Bagnes, Valais, Switzerland), which is an active structurally-controlled instability that threaten roads and inhabitants. The entire slope is included within the Middle Penninic unit. According to regional tectonic stresses, the micaschists that compose the instability have been intensively deformed and metamorphised leading to an important foliation and fracturing. Structural settings have been extracted from 3D points-clouds of the crown area. These datasets were acquired with a terrestrial LiDAR (TLS) and processed with Coltop-3D software. The landslide can be defined as a complex instability, with a continuous movement on a basal surface. This deformation also generates a frequent rockfall activity in the upper part of the slope. The landslide was monitoring using different remote sensing techniques (TLS, GNSS and GB-InSAR): a) regarding TLS measurements, we monitored long term 3D displacements comparing two different TLS points clouds acquired in 2009 and 2011, showing more than 3 m displacements in two years in the upper part of the slope (crown area); b) differential GNSS measures were obtained at the toe of the slide, validating TLS measurements in those areas were vegetation hampered remote sensing measurement; c) finally the landslide was also monitored by a GB-InSAR in order to investigate short term displacements. The experiment was carried out during summer 2011, recording displacement rates exceeding 7 mm in 12 h in the main scarp, and confirmed the high amplitude of daily displacements. We are also continuously recording landslide displacements at a daily rate over the most active part of the slope using one crackmeter. The kinematics of the landslide is characterized by a continuous displacement (3rd creep state) which is clearly controlled by external forces (rainfall episodes): on the one side, landslide velocity sharply increases it value after rainfall episodes; on the other side, landslide velocity is progressively reduced during dry periods, tending to a horizontal asymptote of null displacement. In order to model landslide kinematics, we obtained a response function that reproduces the landslide displacements based on a convolution of daily precipitation during a certain time window (50 days in this case study). Two different response functions following exponential and power laws were tested. The variables of these functions were optimized in Matlab in order to minimize the error between the real and the modeled displacements. The hydrological model shows close resemblance to reality during the calibration period (2007-2008) and is able to forecast landslide displacements during subsequent years. Using both kinematic settings and hydrological approach enables to forecast future displacements according to weather conditions and to establish threshold values a possible early warning system of the Barmasse rockslide.

Michoud, C.; Abellan, A.; Baillifard, F.-J.; Demierre, J.; Derron, M.-H.; Jaboyedoff, M.; Jakubowski, J.; May-Delasoie, F.

2012-04-01

353

Analysis of water flow paths: methodology and example calculations for a potential geological repository in Sweden.  

Science.gov (United States)

Safety assessment related to the siting of a geological repository for spent nuclear fuel deep in the bedrock requires identification of potential flow paths and the associated travel times for radionuclides originating at repository depth. Using the Laxemar candidate site in Sweden as a case study, this paper describes modeling methodology, data integration, and the resulting water flow models, focusing on the Quaternary deposits and the upper 150 m of the bedrock. Example simulations identify flow paths to groundwater discharge areas and flow paths in the surface system. The majority of the simulated groundwater flow paths end up in the main surface waters and along the coastline, even though the particles used to trace the flow paths are introduced with a uniform spatial distribution at a relatively shallow depth. The calculated groundwater travel time, determining the time available for decay and retention of radionuclides, is on average longer to the coastal bays than to other biosphere objects at the site. Further, it is demonstrated how GIS-based modeling can be used to limit the number of surface flow paths that need to be characterized for safety assessment. Based on the results, the paper discusses an approach for coupling the present models to a model for groundwater flow in the deep bedrock. PMID:17334050

Werner, Kent; Bosson, Emma; Berglund, Sten

2006-12-01

354

Parametric analysis of mined geologic disposal of high-level radioactive waste  

International Nuclear Information System (INIS)

A simplified mathematical model has been developed to screen potential mined geological repository sites taking into account the uncertainty in the input data. Initial input data that was assumed constant was inventory of radioactive wastes, number and size of cannisters, size of repository, and the ground water flow area. Though there is some uncertainty in these data, by far the greatest uncertainty pertained to leach rate of the waste form and cannister, ground water velocity, retardation rates of nuclides relative to ground water, distance to the biosphere and flow rate in the receiving waters in the biosphere. These were varied over realistic ranges from 1 to 4 orders of magnitude. The results showed that there are a wide variety of combinations of these parameters that allow a waste repository to be sited without exceeding the maximum permissible concentrations of isotopes in drinking water. It is concluded that for the artificially-created nuclides it is the intermediate time period, greater than 1000 years and less than 1 million years, that poses the greatest problem

355

Metal-silicate extraction technique for the analysis of geological and meteoritic samples  

International Nuclear Information System (INIS)

A simple radiochemical technique was developed for the determination of non-volatile siderophile and lithophile elements in geological samples and meteorites. A thermal neutron irradiated sample is equilibrated with an excess of metallic iron at high temperatures. Metal and silicate phases are manually separated, dissolved and counted on a large Ge(Li) detector. The fraction of lithophile elements in the metal phase are negligible. Elements with siderophile and lithiphile tendencies (e.g. Cr, Fe) distribute between metal and silicate phases. The method is especially well suited for the determination of siderophile elements which have isotopes with half-lives from 10 to 100 hours (Cu, As, Sb, Re, Pt, Au, W, Mo). On the other hand, the background in the silicate phase is considerably reduced because of lack of Fe and Co activities. This enables better determination of elements with long lived isotopes (Hf, Ta etc.). Result obtained from analyses of meteoritic and terrestrial samples demonstrate the reliability and usefulness of the method. (author)

356

The geologic character of nappe structure and its relation to uranium mineralization of Xiangshan ore-field in the middle of Jiangxi Province  

International Nuclear Information System (INIS)

Started with the spatial distribution of nappe structure, the geologic features are discussed and its effect on uranium mineralization in systematically summarized for Xiangshan ore-field in the middle of Jiangxi Province. The nappe structure not only formed a 'cross-over' lithologic combination which creates a network system which can connect, transport, migrate the mineralized matter, but also formed some close or semi-close geologic setting beneath the nappe which can act as the store ore shield space for the mineralized liquid to form uranium deposit. The mineralization is concentrated at the varied place of occurrences or shape of sub-volcanic rocks and the intersection of concealed overthrust and NE strike basic fractures. (authors)

357

Inorganic ion exchangers for the removal of scandium and rare earth elements in neutron activation analysis of geological samples  

International Nuclear Information System (INIS)

Sorption properties of inorganic ion exchangers have been investigated for use in radiochemical separation of elements in geological samples subjected to neutron activation analysis. Samples were allowed to decay for two weeks, dissolved in hydrofluoric acid, and saturated boric acid was added to dissolve any fluoride complexes. Samples were placed onto the COX column and eluted with nitric acid. Retained on the column were scandium 46, zirconium 95, cesium 141, hafnium 181, lanthanum 140, samarium 153, europium 152-154, terbium 160, ytterbium 169, lutetium 177m, prtactinium 233. Present in the eluant were chromium 51, manganese 54, iron 59, cobalt 60, zinc 65, rubidium 81, niobium 95, barium 131, cesium 134, tantalum 182. 1 figure

358

Direct-current arc and alternating-current spark emission spectrographic field methods for the semiquantitative analysis of geologic materials  

Science.gov (United States)

Two spectrographic methods are used in mobile field laboratories of the U. S. Geological Survey. In the direct-current arc method, the ground sample is mixed with graphite powder, packed into an electrode crater, and burned to completion. Thirty elements are determined. In the spark method, the sample, ground to pass a 150-mesh screen, is digested in hydrofluoric acid followed by evaporation to dryness and dissolution in aqua regia. The solution is fed into the spark gap by means of a rotating-disk electrode arrangement and is excited with an alternating-current spark discharge. Fourteen elements are determined. In both techniques, light is recorded on Spectrum Analysis No. 1, 35-millimeter film, and the spectra are compared visually with those of standard films.

Grimes, D.J.; Marranzino, A.P.

1968-01-01

359

Structural analysis of DNA by autoradiography  

International Nuclear Information System (INIS)

During the past 10 years, molecular biology has rapidly been developing owing to easy structural analysis of DNA, a fundamental substance involved in life function. The application of highly sensitive RI with the production of large amounts of DNA and with no change in the chemical property of the substance to be tested has greatly contributed to molecular biology. For the development of life science and biotechnology, it is essential to analyze basic arrangement of DNA, identify genes, predict amino acid arrangement of proteins, and clarify regulation mechanism involved in genes. To understand DNA function suffici