The thermal and deformational history of apollo 15418, A partly shock-melted lunar breccia

USGS Publications Warehouse

Nord, G.L.; Christie, J.M.; Lally, J.S.; Heuer, A.H.

1977-01-01

A thermal and mechanical history of lunar gabbroic anorthosite 15418 (1140g) has been deduced from petrographic examination of both exterior and interior thin sections and electron microprobe analysis and transmission electron microscopy of interior thin sections. We suggest that the rock underwent two major shock events - an early brecciation and annealing that produced a recrystallized breccia, followed by a second shock event that melted the surface of the rock, vitrified the interior plagioclase and heavily deformed the mafic phases. This latter shock even was also followed by annealing which crystallized the shock-produced glass and promoted recovery and recrystallization of the deformed crystalline phases. The complex mechanical and thermal history of 15418 compared with other ANT suite rocks at Spur Crater suggests that it had a different provenance. ?? 1977 D. Reidel Publishing Company, Dordrecht-Holland.

Flue gas desulfurization chemistry studies: limestone grindability. Volume 2. Grindability testing. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richmann, D.L.; Luke, K.W.; Terry, J.C.

1984-07-01

The results of a study to determine the relative grindability of US limestones and to relate grindability to petrographic properties are presented in this report. A laboratory ball mill test was developed to provide a quick and simple measure of grindability. These values were then used to explore possible correlations between grindability and the chemical and physical properties of the limestones. Chemical analyses and thin section petrographic analyses were used to characterize the limestone samples. The results of the laboratory ball mill test were compared to the results of an industrial grinding test, the Bond Work Index, for six samplesmore » which covered the grindability range. The two tests compared well with a correlation coefficient greater than 0.9. While the laboratory test is not sufficient to provide ball mill design specifications, it can be used as a screening and quality control test. The grinding results, expressed as a grindability index, ranged in values from 2 to 15. This represents a seven-fold range in the relative difficulties to grind for the limestones tested. From the petrographic analysis results, a strong correlation was found between the grindability and the fraction of macrocrystalline (> 5 ..mu..m) carbonate minerals present in the limestone. However, based on the high degree of variability characteristic of most limestone deposits, petrographic information should, in general, only be used to qualitatively predict the grindability of a specific limestone. An actual grinding test is recommended for a quantitative evaluation.« less

Lacustrine Environment Reservoir Properties on Sandstone Minerals and Hydrocarbon Content: A Case Study on Doba Basin, Southern Chad

NASA Astrophysics Data System (ADS)

Sumery, N. F. Mohd; Lo, S. Z.; Salim, A. M. A.

2017-10-01

The contribution of lacustrine environment as the hydrocarbon reservoir has been widely known. However, despite its growing importance, the lacustrine petroleum geology has received far less attention than marine due to its sedimentological complexity. This study therefore aims in developing an understanding of the unique aspects of lacustrine reservoirs which eventually impacts the future exploration decisions. Hydrocarbon production in Doba Basin, particularly the northern boundary, for instance, has not yet succeeded due to the unawareness of its depositional environment. The drilling results show that the problems were due to the: radioactive sand and waxy oil/formation damage, which all are related to the lacustrine depositional environment. Detailed study of geological and petrophysical integration on wireline logs and petrographic thin sections analysis of this environment helps in distinguishing reservoir and non-reservoir areas and determining the possible mechanism causing the failed DST results. The interpretations show that the correlation of all types> of logs and rho matrix analysis are capable in identifying sand and shale bed despite of the radioactive sand present. The failure of DST results were due to the presence of arkose in sand and waxy oil in reservoir bed. This had been confirmed by the petrographic thin section analysis where the arkose has mineral twinning effect indicate feldspar and waxy oil showing bright colour under fluorescent light. Understanding these special lacustrine environment characteristics and features will lead to a better interpretation of hydrocarbon prospectivity for future exploration.

Three Microstructural Exercises for Students.

ERIC Educational Resources Information Center

Means, Winthrop D.

1986-01-01

Describes laboratory exercises which demonstrate a new simplified technique for deforming thin samples of crystalline materials on the stage of a petrographic microscope. Discusses how this process allows students to see the development of microstructures resulting from cracking, slipping, thinning, and recrystallization. References and sources of…

Growth of contact area between rough surfaces under normal stress

NASA Astrophysics Data System (ADS)

Stesky, R. M.; Hannan, S. S.

1987-05-01

The contact area between deforming rough surfaces in marble, alabaster, and quartz was measured from thin sections of surfaces bonded under load with low viscosity resin epoxy. The marble and alabaster samples had contact areas that increased with stress at an accelerating rate. This result suggests that the strength of the asperity contacts decreased progressively during the deformation, following some form of strain weakening relationship. This conclusion is supported by petrographic observation of the thin sections that indicate that much of the deformation was cataclastic, with minor twinning of calcite and kinking of gypsum. In the case of the quartz, the observed contact area was small and increased approximately linearly with normal stress. Only the irreversible cataclastic deformation was observed; however strain-induced birefringence and cracking of the epoxy, not observed with the other rocks, suggests that significant elastic deformation occurred, but recovered during unloading.

Fluid inclusion geothermometry

USGS Publications Warehouse

Cunningham, C.G.

1977-01-01

Fluid inclusions trapped within crystals either during growth or at a later time provide many clues to the histories of rocks and ores. Estimates of fluid-inclusion homogenization temperature and density can be obtained using a petrographic microscope with thin sections, and they can be refined using heating and freezing stages. Fluid inclusion studies, used in conjunction with paragenetic studies, can provide direct data on the time and space variations of parameters such as temperature, pressure, density, and composition of fluids in geologic environments. Changes in these parameters directly affect the fugacity, composition, and pH of fluids, thus directly influencing localization of ore metals. ?? 1977 Ferdinand Enke Verlag Stuttgart.

Influences of petrographic parameters on technological properties of greywackes used for crushed stone production

NASA Astrophysics Data System (ADS)

Prikryl, Richard; Cermak, Martin; Krutilova, Katerina

2014-05-01

This study focuses on the influence of petrographic parameters on technological properties of greywackes. These sedimentary rocks make about 27 % of crushed stone market in the Czech Republic. Mainly in Moravia (eastern part of the Czech Republic), greywackes represent almost exclusive high quality aggregate. The behaviour of greywackes varies, however, from quarry to quarry. In this study, we have selected the most important deposits that cover major lithological variation of local greywackes. Studied greywackes were analysed for their petrographic parameters quantitatively (using image analysis of thin sections). The pore space characteristics were determined by using fluorescent dye - epoxy resin impregnated specimens. The studied rocks are composed of subangular and angular quartz grains, lithoclasts (stable rocks: quartzites, and unstable rocks: phylites, metaphylites, siltstones, slates, greywackes, and less frequently acid eruptive rocks), feldspars (orthoclas, microcline, plagioclase), and detrital micas. Detrital and authigenic chlorite has been found as well. The matrix which represents the largest volume of rock-forming components contains a mixture of sericite, chlorite, clay minerals, cements, and clasts in aleuropelitic size. Based on the microscopic examination, all studied rock types were classified as greywacke with fine- to medium-grained massive rock fabric. Only specimen from Bělkovice has shown partly layered structure. Alteration of feldspars and unstable rock fragments represents common feature. Diagenetic features included pressure dissolution of quartz clasts and formation of siliceous and/or calcite cements. Based on the experimental study of technological performance of studied greywackes and its correlation to petrographic features, the average size of clasts and volume of matrix make the driving factors affecting the LA values. The LA values decrease with the increasing of volume of matrix (R = 0.61) and with decreasing average grain size (R = 0.44). The degree of sorting influences LA values as well; more graded greywackes tend to show higher LA values. Regarding PSV, its values increase with increasing volume of quartz clasts.

Petrographic characterization and provenance determination of the white marbles used in the Roman sculptures of Forum Sempronii (Fossombrone, Marche, Italy)

NASA Astrophysics Data System (ADS)

Antonelli, Fabrizio; Columbu, Stefano; Lezzerini, Marco; Miriello, Domenico

2014-06-01

The Roman municipium of Forum Sempronii (Fossombrone, Marche) was located along the `Via Consolare Flaminia', in the stretch of road where it ran along the final sector of the valley of the River Metauro ( Mataurus). The ancient colony of Forum Sempronii, which is cited by Strabo, Pliny, and Ptolemy, was found in the second century BC, probably on the site of an earlier community and its activity continued until the end of the fifth century AD. During ancient and more recent archaeological excavations, many fragments of coloured stones and marbles, and some white marble sculptures have been unearthed. In this paper, we report the results of the provenance identification of the white marbles used for the sculptures found in the archaeological site of Forum Sempronii and now displayed at the local archaeological museum. The determination of the source origin of the white marbles used for the sculptures has been established by mineralogical-petrographic and geochemical analyses. Microscopic study of thin sections together with carbon and oxygen stable isotope ratios indicate that more than one type of white marbles was used: Pentelikon, Lunense, and Thasian.

Particle Shape Characterization of Lunar Regolith using Reflected Light Microscopy

NASA Astrophysics Data System (ADS)

McCarty, C. B.; Garcia, G. C.; Rickman, D.

2014-12-01

Automated identification of particles in lunar thin sections is necessary for practical measurement of particle shape, void characterization, and quantitative characterization of sediment fabric. This may be done using image analysis, but several aspects of the lunar regolith make such automations difficult. For example, many of the particles are shattered; others are aggregates of smaller particles. Sieve sizes of the particles span 5 orders of magnitude. The physical thickness of a thin section, at a nominal 30 microns, is large compared to the size of many of the particles. Image acquisition modes, such as SEM and reflected light, while superior to transmitted light, still have significant ambiguity as to the volume being sampled. It is also desirable to have a technique that is inexpensive, not resource intensive, and analytically robust. To this end, we have developed an image acquisition and processing protocol that identifies and delineates resolvable particles on the front surface of a lunar thin section using a petrographic microscope in reflected light. For a polished thin section, a grid is defined covering the entire thin section. The grid defines discrete images taken with 20% overlap, minimizing the number of particles that intersect image boundaries. In reflected light mode, two images are acquired at each grid location, with a closed aperture diaphragm. One image, A, is focused precisely on the front surface of the thin section. The second image, B, is made after the stage is brought toward the objective lens just slightly. A bright fringe line, analogous to a Becke line, appears inside all transparent particles at the front surface of the section in the second image. The added light in the bright line corresponds to a deficit around the particles. Particle identification is done using ImageJ and uses multiple steps. A hybrid 5x5 median filter is used to make images Af and Bf. This primarily removes very small particles just below the front surface of the section. Bf - (Bf/Af) is then computed. The division strongly enhances the fringe and the deficit, while minimizing the correlated information in A and B. The subtraction emphasizes the particle-epoxy boundaries. The resulting image is converted to binary, and then holes are filled. Cracks are removed using a median-based operator.

The Central Asiatic (Tibet, Xinjiang, Pamir) petrological collections of Sven Hedin (1865 1952) — Swedish explorer and adventurer

NASA Astrophysics Data System (ADS)

Weinberg, Roberto F.; Green, Owen R.

2002-02-01

During a 42 year period (1893-1935), the Swedish explorer Sven Hedin led and co-ordinated four expeditions to remote and inhospitable parts of Central Asia (Tibet, Xinjiang, Pamir). Along with collaborators he collected a diverse collection of just under 3100 petrological specimens. Petrographic examples of high pressure metamorphic blueschists, mantle peridotites and serpentinites, granitoids, K-rich alkaline lavas, mylonites, and a range of clastic and fossil rich carbonate sedimentary rocks are present. This collection is a major asset for scientists studying the history of continental collision between India and Asia, and the uplift of the Tibetan plateau. A spreadsheet listing all the samples collected during Hedin's first three expeditions into Tibet (commencing 1893, 1899, 1906) includes a brief description and location of each specimen, with additional information on the availability of thin sections. Samples are cross-referenced with the geographical position of Hedin's campsites indicated on maps published with his extensive reports. Most samples, and a number of thin sections, are available for loan from the Swedish Museum of Natural History, Stockholm. We also describe a smaller collection of specimens and thin sections from Hedin's fourth (1927-35, Sino-Swedish) expedition, currently housed at the Institute of Earth Sciences, Uppsala University. Hedin's career as an explorer, highlighting the geological significance of his work and the reasons that it has remained largely ignored by the majority of Himalayan and Central Asian researchers for so many years, is outlined.

Petrographic and petrological studies of lunar rocks. [from the Apollo 15 mission

NASA Technical Reports Server (NTRS)

Winzer, S. R.

1978-01-01

Thin sections and polished electron probe mounts of Apollo 15 glasscoated breccias 15255, 15286, 15466, and 15505 were examined optically and analyzed by sem/microprobe. Sections from breccias 15465 and 15466 were examined in detail, and chemical and mineralogical analyses of several larger lithic clasts, green glass, and partly crystallized green glass spheres are presented. Area analyses of 33 clasts from the above breccias were also done using the SEM/EDS system. Mineralogical and bulk chemical analyses of clasts from the Apollo 15 glass-coated breccias reveal a diverse set of potential rock types, including plutonic and extrusive igneous rocks and impact melts. Examination of the chemistry of the clasts suggests that many of these clasts, like those found in 61175, are impact melts. Their variability suggests formation by several small local impacts rather than by a large basin-forming event.

Non-Destructive Classification Approaches for Equilbrated Ordinary Chondrites

NASA Technical Reports Server (NTRS)

Righter, K.; Harrington, R.; Schroeder, C.; Morris, R. V.

2013-01-01

Classification of meteorites is most effectively carried out by petrographic and mineralogic studies of thin sections, but a rapid and accurate classification technique for the many samples collected in dense collection areas (hot and cold deserts) is of great interest. Oil immersion techniques have been used to classify a large proportion of the US Antarctic meteorite collections since the mid-1980s [1]. This approach has allowed rapid characterization of thousands of samples over time, but nonetheless utilizes a piece of the sample that has been ground to grains or a powder. In order to compare a few non-destructive techniques with the standard approaches, we have characterized a group of chondrites from the Larkman Nunatak region using magnetic susceptibility and Moessbauer spectroscopy.

Timing of compaction and quartz cementation from integrated petrographic and burial-history analyses, Lower Cretaceous Fall River Formation, Wyoming and South Dakota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutton, S.P.

1997-01-01

Integrated petrographic and burial-history studies of Fall River sandstones from outcrop and the subsurface provide insight into the timing of compaction and quartz cementation, the two main porosity-reducing processes in quartzose sandstones. Petrographic study of 95 thin sections of Fall River fluvial valley-fill sandstones from outcrop, Donkey Creek field at 2 km burial depth, and Buck Draw field at 3.8 km indicates that reservoir quality differs significantly in these three areas. Fall River sandstones at the surface contain an average of 31% intergranular volume (IGV) and 2% quartz cement. In both Donkey Creek and Buck Draw fields, the sandstones averagemore » 22% IGV, but quartz-cement volume averages 8% in the shallower field and 12% in the deeper. Geometric mean permeability at the surface is 4,700 md, compared with 42 md at 2 km and 2 md at 3.8 km. Burial history of the Fall River sandstone differs greatly in the three areas. The outcropping sandstones were buried to 2 km and had reached 80 C by the end of the Cretaceous. They were then uplifted and have remained at near-surface temperatures since the Paleocene; the calculated time-temperature index (TTI) of these sandstones is 1. Fall River sandstones at Donkey Creek were also buried to 2 km and had reached 80 C by the end of the Cretaceous but remained at that depth during the Tertiary; TTI is 14. In Buck Draw field, Fall River sandstones were buried to 2.5 km during the Cretaceous and then continued to subside during the Tertiary, reaching depths of 4 km and temperatures of 140 C; TTI is 512.« less

Examining the Real Merits of the Virtual Microscope

NASA Astrophysics Data System (ADS)

Hennessy, Ronan; Meere, Pat; Ho, Timsie; Menuge, Julian; Tyrrell, Shane; Kamber, Balz; Higgs, Bettie; Kelley, Simon

2017-04-01

The Geoscience e-Laboratory (GeoLAB) project is a cooperative digital petrological microscopy technology enhanced learning (TEL) resource development project involving the four main university geoscience teaching centres in Ireland. Collaborating with the Open University (UK), a new digital library of petrographic thin sections has been added to the Virtual Microscope for Earth Sciences (VMfES) online repository. The collection was compiled with a view to introducing high-quality samples to teaching programmes in a manner that hitherto was limited by sample and microscope availability and cost and the temporal limits of laboratory access. The project has proceeded to explore the pedagogical implications of using the Virtual Microscope in teaching programmes. Online assessments and self-guided exercises developed using applications such as Google Forms have been introduced into programmes at each centre, and complimented by tutorial and interactive videos designed to support self-guided learning. The GeoLab project is reporting on the pedagogical implications of providing students with unimpeded access to high-quality petrographic learning resources during the term of semester and in advance of student assessments. Additionally, the project is collating data on the perceptions of both teachers and learners to using online learning media in mineralogy and petrology programmes, and if there are benefits therein to the more traditional styles of petrology and microscopy teaching and learning.

Probable hepatic capillariosis and hydatidosis in an adolescent from the late Roman period buried in Amiens (France).

PubMed

Mowlavi, Gholamreza; Kacki, Sacha; Dupouy-Camet, Jean; Mobedi, Iraj; Makki, Mahsasadat; Harandi, Majid Fasihi; Naddaf, Saied Reza

2014-01-01

Two calcified objects recovered from a 3rd to 4th-century grave of an adolescent in Amiens (Northern France) were identified as probable hydatid cysts. By using thin-section petrographic techniques, probable Calodium hepaticum (syn. Capillaria hepatica) eggs were identified in the wall of the cysts. Human hepatic capillariosis has not been reported from archaeological material so far, but could be expected given the poor level of environmental hygiene prevalent in this period. Identification of tissue-dwelling parasites such as C. hepaticum in archaeological remains is particularly dependent on preservation conditions and taphonomic changes and should be interpreted with caution due to morphological similarities with Trichuris sp. eggs. © G. Mowlavi et al., published by EDP Sciences, 2014.

High resolution ion microprobe investigation of the δ18O of carbonate cements (Jurassic, Paris Basin, France): New insights and pending questions

NASA Astrophysics Data System (ADS)

Vincent, Benoit; Brigaud, Benjamin; Emmanuel, Laurent; Loreau, Jean-Paul

2017-04-01

The scope of this work is to investigate, at a high resolution, the oxygen isotope composition (δ18Ocarb) of diagenetic products (synsedimentary and burial calcite cements) in shallow-marine carbonates. SIMS (Secondary Ion Mass Spectrometry) microprobe analyses were performed on thin sections from Oxfordian and Kimmeridgian Formations of the eastern Paris Basin and compared to data obtained on the same diagenetic products by conventional mass spectrometry (acid digestion). Hereby obtained, δ18O are similar, but the SIMS dataset displays a larger range of values. The isotopic zonation obtained by SIMS transects through sequences of cements filling pores, reveals an (expected) isotopic depletion from older stage synsedimentary calcites to younger stage blocky calcites and that follows the CL (cathodoluminescence) zonation. SIMS analyses however show that synsedimentary cements precipitated in intra-skeletal pores, have heavier δ18O than their inter-particle counterparts, with an offset of + 4‰V-PDB, despite similar petrographical characteristics. This difference is maintained in the δ18O of the first stages of blocky calcite cements, intra-skeletal blocky calcites showing heavier δ18O than the time equivalent and petrographically identical inter-particle calcites, with an offset of + 5‰V-PDB. These offsets are tentatively explained by the precipitation of cements under non-equilibrium conditions in intra-skeletal pores, where organic matter decay may have played a key role, acting notably on the pH. The occurrence of isolated micro-diagenetic environments, co-existing at the thin section scale, is tentatively proposed as an explanation to these small scale and high amplitude δ18O heterogeneities. These results may question the sampling strategy for future works. Microdrilling may miss the observed range of variation, but averaging the values may not necessarily lead to real misinterpretations if a critical selection of samples is performed, targeting potentially similar micro-diagenetic environments and avoiding potentially specific ones, i.e. closed intra-skeletal pores. These results also definitely underscore the need for additional experiments to improve the reliability of SIMS, in order to develop the use of this very high resolution technique for carbonate diagenesis studies.

Transient calcite fracture fillings in a welded tuff, Snowshoe Mountain, Colorado

USGS Publications Warehouse

Hoch, A.R.; Reddy, M.M.; Heymans, M.J.

2000-01-01

The core from two boreholes (13.1 and 19.2 m depth) drilled 500 m apart in the fractured, welded tuff near the summit of the Snowshoe Mountain, Colorado (47??30'N, 106??55'W) had unique petrographic and hydrodynamic properties. Borehole SM-4 had highly variable annual water levels, in contrast to SM-1a, whose water level remained near the land surface. Core samples from both boreholes (n = 10 and 11) were examined petrographically in thin sections impregnated with epoxy containing rhodamine to mark the pore system features, and were analyzed for matrix porosity and permeability. Core from the borehole sampling the vadose zone was characterized by open fractures with enhanced porosity around phenocrysts due to chemical weathering. Fractures within the borehole sampling the phreatic zone were mineralized with calcite and had porosity characteristics similar to Unweathered and unfractured rock. At the top of the phreatic zone petrography indicates that calcite is dissolving, thereby changing the hydrogeochemical character of the rock (i.e. permeability, porosity, reactive surface area, and mineralogy). Radiocarbon ages and C and O stable isotopes indicate that calcite mineralization occurred about 30 to 40 ka ago and that there was more than one mineralization event. Results of this study also provide some relationships between primary porosity development from 3 types of fracture in a welded tuff. (C) 2000 Elsevier Science Ltd.

Stratigraphic charcoal analysis on petrographic thin sections: Application to fire history in northwestern Minnesota

NASA Astrophysics Data System (ADS)

Clark, James S.

1988-07-01

Results of stratigraphic charcoal analysis from thin sections of varved lake sediments have been compared with fire scars on red pine trees in northwestern Minnesota to determine if charcoal data accurately reflect fire regimes. Pollen and opaque-spherule analyses were completed from a short core to confirm that laminations were annual over the last 350 yr. A good correspondence was found between fossil-charcoal and fire-scar data. Individual fires could be identified as specific peaks in the charcoal curves, and times of reduced fire frequency were reflected in the charcoal data. Charcoal was absent during the fire-suppression era from 1920 A.D. to the present. Distinct charcoal maxima from 1864 to 1920 occurred at times of fire within the lake catchment. Fire was less frequent during the 19th century, and charcoal was substantially less abundant. Fire was frequent from 1760 to 1815, and charcoal was abundant continuously. Fire scars and fossil charcoal indicate that fires did not occur during 1730-1750 and 1670-1700. Several fires occurred from 1640 to 1670 and 1700 to 1730. Charcoal counted from pollen preparations in the area generally do not show this changing fire regime. Simulated "sampling" of the thin-section data in a fashion comparable to pollen-slide methods suggests that sampling alone is not sufficient to account for differences between the two methods. Integrating annual charcoal values in this fashion still produced much higher resolution than the pollen-slide method, and the postfire suppression decline of charcoal characteristic of my method (but not of pollen slides) is still evident. Consideration of the differences in size of fragments counted by the two methods is necessary to explain charcoal representation in lake sediments.

Petrographic Evidence of Microbial Mats in the Upper Cretaceous Fish-Bearing, Organic-Rich Limestone, Agua Nueva Formation, Central Mexico

NASA Astrophysics Data System (ADS)

Blanco, A.; Maurrasse, F. J.; Hernández-Ávila, J.; Ángeles-Trigueros, S. A.; García-Cabrera, M. E.

2013-05-01

We document petrographic evidence of microbial mats in the Upper Cretaceous Agua Nueva Formation in the area of Xilitla (San Luis Potosí, Central Mexico), located in the southern part of the Tampico-Misantla basin. The sequence consists predominantly of alternating decimeter-thick beds of fossiliferous dark laminated limestone (C-org > 1.0wt%), and light gray, bioturbated limestone (C-org < 1.0wt%), with occasional brown shale and green bentonite layers. Well-preserved fossil-fish assemblages occur in the laminated dark limestone beds, which include shark teeth (cf. Ptychodus), scales of teleosteans (Ichthyodectiformes), as well as skeletal remains of holosteans (Nursallia. sp), and teleosteans (cf. Rhynchodercetis, Tselfatia, and unidentified Enchodontids). Thin section and SEM analyses of the laminated, dark limestones, reveal a micritic matrix consisting of dark and light sub-parallel wavy laminae, continuous and discontinuous folded laminae with shreds of organic matter, filaments, oncoids, and interlocking structures. The structures are identical to those previously described for the Cenomanian-Turonian Indidura Fm at Parras de la Fuente (Coahuila state) demonstrated to be of microbial origin (Duque-Botero and Maurrasse, 2005; 2008). These structures are also analogous to microbial mats in present environments, and Devonian deposits (Kremer, 2006). In addition, the laminae at Xilitla include filamentous bacterial structures, as thin and segmented red elements. In some thin sections, filaments appear to be embedded within the crinkly laminae and shreds showing the same pattern of folding, suggestive of biomorphic elements that represent the main producers of the organic matter associated with the laminae. Thus, exceptional bacterial activity characterizes sedimentation during the accumulation of the Agua Nueva Formation. Oxygen-deficient conditions related to the microbial mats were an important element in the mass mortality and preservation of the fish assemblages. Absence of bioturbation, pervasive framboidal pyrite, and the high concentration of organic matter (TOC ranges from 1.2% to 8wt%) in the dark limestones are consistent with persistent recurring dysoxic/anoxic conditions, and the light-gray bioturbated limestones represent relatively well-oxygenated episodes. Planktonic foraminifera (Rotalipora cushmani) and Inoceramu labiatus indicate a time interval from the latest Cenomanian through the earliest Turonian, thus this long interval of severe oxygen deficiency is coeval with Oceanic Anoxic Event 2 (OAE-2). [Duque-Botero and Maurrasse. 2005. Jour. Iberian Geology (31), 85-98; 2008. Cret. Res., 29, 957-964; Kremer. 2006. Acta Palaeontologica Polonica (51, 1), 143-154

Petrographic and geochemical investigation of magma chamber processes beneath small Quaternary volcanic centers between Mt. Jefferson and Mt. Hood volcanoes, Cascade Range Volcanic Arc

NASA Astrophysics Data System (ADS)

Cunningham, E.; Cribb, J. W.

2017-12-01

The northern Oregon Cascade Range has been dominated by andesite to rhyodacite lavas at both Mt. Jefferson (Conrey, 1991) and at Mt. Hood (Cribb and Barton, 1996) during the Quaternary period. Eruptive sequences at both Mt. Hood and Mt. Jefferson have been attributed to open-system mama mixing (Kent et al., 2010) (Ferrell et al., 2015), and the narrow range of lavas erupted at both centers has been derived from repeated cycles of magma mixing-fractionation (Cribb and Barton, 1996). This research examines major and trace element geochemistry as well as the petrographic characteristics of Clear Lake Butte (CLB), Pinhead Butte (PB), and Olallie Butte (OB), all of which are located between Mt. Hood and Mt. Jefferson, and have ben active in the Quaternary period. The research investigates whether the same type of open-system magma mixing known to have occurred at Mt. Hood and Mt. Jefferson has also occurred at CLB, PB, or OB, or whether those systems were closed to mixing and dominated by fractional crystallization. One of the main goals of this project is to highlight the similarities and differences exhibited by neighboring magmatic systems of similar age, but different scale. Disequilibrium textures observed in thin sections from CLB, OB, and PB suggest open-system magma mixing is likely occurring beneath all three buttes. This petrographic evidence includes plagioclase and pyroxene zoning, embayed margins, sieving, and reaction rims. Major element oxide trends at all three buttes are consistent with fractional crystallization, but show narrow concentrations and non-overlapping compositions between PB, CLB, and OB. All three buttes are characterized by narrow ranges of incompatible and compatible trace element concentrations. CLB, PB, and OB all exhibit LREE enrichment and lack significant HFSE depletions, with PB exhibiting greatest enrichment in REE.

Us army corps of engineers - Engineering research and development center - Petrographic analysis of section 3 personnel tunnel concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, J. M.

The Concrete and Materials Branch (CMB) of the Geotechnical and Structures Laboratory was requested to perform an analysis on concrete cores collected from the north and south walls of the H-Canyon Section 3 Personnel Tunel, Savannah River Site, Aiken, South Carolina to determine the cause of the lower than expected compressive strength. This study examined five cores provided to the ERDC by the Department of Energy. The cores were logged in as CMB No. 170051-1 to 170051-5 and subjected to petrographic examination, air void analysis, chemical sprays, scanning electron microscopy, and x-ray diffraction.

Description and hydrogeologic implications of cored sedimentary material from the 1975 drilling program at the radioactive waste management complex, Idaho

USGS Publications Warehouse

Rightmire, C.T.

1984-01-01

Samples of sedimentary material from interbeds between basalt flows and from fractures in the flows, taken from two drill cores at the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory were analyzed for (1) particle-size dribution, (2) bulk mineralogy, (3) clay mineralogy, (4) cation-exchange capacity, and (5) carbonate content. Thin sections of selected sediment material were made for petrographic examination. Preliminary interpretations indicate that (1) it may be possible to distinguish the various sediment interbeds on the basis of their mineralogy, (2) the presence of carbonate horizons in sedimentary interbeds may be utilized to approximate the time of exposure and the climate while the surface was exposed (which affected the hydrogeologic character of the sediment), and the type and orientation of fracture-filling material may be utilized to determine the mechanism by which fractures were filled. (USGS)

Petrography, geochemistry, and depositional setting of the San Pedro and Santo Tomas coal zones: Anomalous algae-rich coals in the middle part of the Claiborne Group (Eocene) of Webb County, Texas

USGS Publications Warehouse

Warwick, Peter D.; Hook, Robert W.

1995-01-01

Two coal zones, the San Pedro and the overlying Santo Tomas, are present for nearly 35 km in outcrop, surface and underground mines, and shallow drill holes along the strike of the middle part of the Claiborne Group (Eocene) in Webb County, Texas. A sandstone-dominated interval of 25 to 35 m separates the two coal zones, which range up to 3 m in thickness. Each coal zone contains carbonaceous shales, thin (<0.75 m) impure coal beds, and thin (<0.85 m) but commercially significant nonbanded coal beds. The nonbanded coals are different from other Tertiary coals of the Gulf of Mexico Coastal Plain: unlike lignites that are typical of the older Wilcox Group (Paleocene-Eocene) and younger Jackson Group (Eocene), nonbanded coals of the Claiborne Group have high vitrinite-reflectance values (0.53 Rmax) and high calorific yields (average 6670 kcal/kg or 12,000 Btu, dry basis). The coals are weakly agglomerating (free-swelling index is 1.5–2.0) and have an apparent rank of high-volatile bituminous.The coal-bearing portion of the middle Claiborne Group in the Rio Grande area represents a fining-upward transition from sandstone-dominated, marine-influenced, lower delta plain depositional environments to more inland, mudstone-rich, predominantly freshwater deltaic settings. Discontinuities within the San Pedro coal zone are attributed mainly to the influence of contemporaneous deposition of distributary mouth-bar sand bodies. The less variable nature of the Santo Tomas coal zone reflects its origin in the upper part of an interlobe basin that received only minor clastic influx.Petrographic attributes of the nonbanded coals indicate that they formed subaqueously in fresh to possibly brackish waters. A highly degraded groundmass composed of eugelinite is the main petrographic component (approximately 71%, mineral-matter-free basis). An enriched liptinite fraction (approximately 23%) probably accounts for unusually high calorific values. There is negligible inertinite. Petrographic study of polished blocks indicates that approximately 10 percent of the nonbanded coal from both coal zones is composed of green algae fructifications, which also occur in clastic rocks of the coal-bearing interval. Such algal material cannot be identified or quantified by conventional coal petrographic techniques that utilize particle pellets or by palynological analyses that include acid preparation.

3D Seismic Reflection Amplitude and Instantaneous Frequency Attributes in Mapping Thin Hydrocarbon Reservoir Lithofacies: Morrison NE Field and Morrison Field, Clark County, KS

NASA Astrophysics Data System (ADS)

Raef, Abdelmoneam; Totten, Matthew; Vohs, Andrew; Linares, Aria

2017-12-01

Thin hydrocarbon reservoir facies pose resolution challenges and waveform-signature opportunities in seismic reservoir characterization and prospect identification. In this study, we present a case study, where instantaneous frequency variation in response to a thin hydrocarbon pay zone is analyzed and integrated with other independent information to explain drilling results and optimize future drilling decisions. In Morrison NE Field, some wells with poor economics have resulted from well-placement incognizant of reservoir heterogeneities. The study area in Clark County, Kanas, USA, has been covered by a surface 3D seismic reflection survey in 2010. The target horizon is the Viola limestone, which continues to produce from 7 of the 12 wells drilled within the survey area. Seismic attributes extraction and analyses were conducted with emphasis on instantaneous attributes and amplitude anomalies to better understand and predict reservoir heterogeneities and their control on hydrocarbon entrapment settings. We have identified a higher instantaneous frequency, lower amplitude seismic facies that is in good agreement with distinct lithofacies that exhibit better (higher porosity) reservoir properties, as inferred from well-log analysis and petrographic inspection of well cuttings. This study presents a pre-drilling, data-driven approach of identifying sub-resolution reservoir seismic facies in a carbonate formation. This workflow will assist in placing new development wells in other locations within the area. Our low amplitude high instantaneous frequency seismic reservoir facies have been corroborated by findings based on well logs, petrographic analysis data, and drilling results.

Petrographic Analyses of Lonestones from ODP Drill Sites Leg 188 Prydz Bay, Antarctica

NASA Astrophysics Data System (ADS)

Detterman, K.; Warnke, D. A.; Richter, C.

2006-12-01

ODP Leg 188 was drilled in 2000 to sample the first advances of the Antarctic ice sheet and to document further cryospheric development. Continental shelf Site 1166 documented the earliest stages of glaciation during the Eocene-Oligocene and continental slope Site 1167 documented rapid deposition by debris flows during the Pliocene-Pleistocene and a subtle change in onshore erosion areas. Site 1165, located on the continental rise, documented long-term transition from wet-based lower Miocene glaciers to dry-based upper Miocene glaciers, including short-term fluctuations starting in the early Miocene. Source areas for all drill sites are the Lambert Glacier-Amery Ice Shelf drainage area, encompassing the Northern and Southern Prince Charles Mountains, the Gamburtsev Sub-glacial Mountains, and the Grove Mountains. Lonestones occur in most of the cores from all sites of Leg 188 prompting research for potential source areas and transportation modes of the lonestones. One-hundred and seventeen thin sections of lonestones were prepared from Sites 1166, 1167, and 1165 for petrographic analyses. Metamorphic lonestones outnumber igneous and sedimentary lonestones at all three sites. Sedimentary lonestones were not found in the thin sections of Site 1166. Extrusive igneous lonestones were found only at Site 1165 and comprised 5.1 percent of Leg 188's lithology. The anorthite content of igneous and metamorphic lonestones represented at all three sites was albite-oligoclase plagioclase. Albite oligoclase plagioclase has been documented in the Southern Prince Charles Mountains. The results of this study of a selection of lonestones from Site 1167 supports a hypothesis first proposed by the Shipboard Scientific Party in 2001 that as time elapsed, the source area for Site 1167 lonestones shifted slightly from a largely sandstone source to a largely granitic source within the drainage area. One potential source area for the Site 1167 sandstone lonestones is the Permian to Triassic Amery Group in the Beaver Lake area of the Northern Prince Charles Mountains. We hypothesize that more easily eroded portions of the sandstone outcrops were planed off first while ubiquitous gneiss and granite outcrops provided the source material for the younger debris flows at Site 1167 in the Pliocene-Pleistocene. None of all the available lonestones suggest sources other than the drainage area of the Lambert Glacier- Amery Ice Shelf complex.

Analytical performance of a versatile laboratory microscopic X-ray fluorescence system for metal uptake studies on argillaceous rocks

NASA Astrophysics Data System (ADS)

Gergely, Felicián; Osán, János; Szabó, B. Katalin; Török, Szabina

2016-02-01

Laboratory-scale microscopic X-ray fluorescence (micro-XRF) plays an increasingly important role in various fields where multielemental investigations of samples are indispensable. In case of geological samples, the reasonable detection limits (LOD) and spatial resolutions are necessary to identify the trace element content in microcrystalline level. The present study focuses on the analytical performance of a versatile laboratory-scale micro-XRF system with various options of X-ray sources and detectors to find the optimal experimental configuration in terms of sensitivities and LOD for selected elements in loaded petrographic thin sections. The method was tested for sorption studies involving thin sections prepared from cores of Boda Claystone Formation, which is a potential site for a high-level radioactive waste repository. Loaded ions in the sorption measurements were Cs(I) and Ni(II) chemically representing fission and corrosion products. Based on the collected elemental maps, the correlation between the elements representative of main rock components and the selected loaded ion was studied. For the elements of interest, Cs(I) and Ni(II) low-power iMOXS source with polycapillary and silicon drift detector was found to be the best configuration to reach the optimal LOD values. Laboratory micro-XRF was excellent to identify the responsible key minerals for the uptake of Cs(I). In case of nickel, careful corrections were needed because of the relatively high Ca content of the rock samples. The results were compared to synchrotron radiation micro-XRF.

Gold paragenesis and chemistry at Batu Hijau, Indoneisa: implications for gold-rich porphyry copper deposits

NASA Astrophysics Data System (ADS)

Arif, J.; Baker, T.

2004-10-01

Gold is an important by-product in many porphyry-type deposits but the distribution and chemistry of gold in such systems remains poorly understood. Here we report the results of petrographic, electron microprobe, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and flotation test studies of gold and associated copper sulfides within a paragenetic framework from the world-class Batu Hijau (914 mt @ 0.53% Cu, 0.40 g/t Au) porphyry copper gold deposit, Indonesia. Unlike many other porphyry copper gold deposits, early copper minerals (bornite digenite chalcocite) are well preserved at Batu Hijau and the chalcopyrite pyrite overprint is less developed. Hence, it provides an excellent opportunity to study the entire gold paragenesis of the porphyry system. In 105 polished thin sections, 699 native gold grains were identified. Almost all of the native gold grains occurred either within quartz veins, attached to sulfide, or as free gold along quartz or silicate grain boundaries. The native gold grains are dominantly round in shape and mostly 1 12 μm in size. The majority of gold was deposited during the formation of early ‘A’ veins and is dominantly associated with bornite rather than chalcopyrite. The petrographic and LA-ICP-MS study results indicate that in bornite-rich ores gold mostly occurs within copper sulfide grains as invisible gold (i.e., within the sulfide structure) or as native gold grains. In chalcopyrite-rich ores gold mostly occurs as native gold grains with lesser invisible gold. Petrographic observations also indicate a higher proportion of free gold (native gold not attached to any sulfide) in chalcopyrite-rich ores compared to bornite rich ores. The pattern of free gold distribution appears to correlate with the flotation test data, where the average gold recovery value from chalcopyrite-rich ores is consistently lower than bornite-rich ores. Our data suggest that porphyry copper-gold deposits with chalcopyrite-rich ores are more likely to have a higher proportion of free gold and may require different ore processing strategies.

Quantitative assessment of alkali-reactive aggregate mineral content through XRD using polished sections as a supplementary tool to RILEM AAR-1 (petrographic method)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Castro, Nelia, E-mail: nelia.castro@ntnu.no; Sorensen, Bjorn E.; Broekmans, Maarten A.T.M.

The mineral content of 5 aggregate samples from 4 different countries, including reactive and non-reactive aggregate types, was assessed quantitatively by X-ray diffraction (XRD) using polished sections. Additionally, electron probe microanalyzer (EPMA) mapping and cathodoluminescence (CL) were used to characterize the opal-CT identified in one of the aggregate samples. Critical review of results from polished sections against traditionally powdered specimen has demonstrated that for fine-grained rocks without preferred orientation the assessment of mineral content by XRD using polished sections may represent an advantage over traditional powder specimens. Comparison of data on mineral content and silica speciation with expansion data frommore » PARTNER project confirmed that the presence of opal-CT plays an important role in the reactivity of one of the studied aggregates. Used as a complementary tool to RILEM AAR-1, the methodology suggested in this paper has the potential to improve the strength of the petrographic method.« less

Comparison of the petrography, palynology, and paleobotany of the Little Fire Creek coal bed, southwestern Virginia, USA

USGS Publications Warehouse

Pierce, B.S.; Eble, C.F.; Stanton, R.W.

1995-01-01

The proximate, petrographic, palynologic, and plant tissue data from two sets of samples indicate a high ash, gelocollinite- and liptinite-rich coal consisting of a relatively diverse paleoflora, including lycopsid trees, small lycopsids, tree ferns, small ferns, pteridosperms, and rare calamites and cordaites. The relatively very high ash yields the relatively thin subunits and the large scale vertical variations in palynomorph floras suggest that the study area was at the edge of the paleopeat-forming environment. -from Authors

Compositional and Microtextural Analysis of Basaltic Feedstock Materials Used for the 2010 ISRU Field Tests, Mauna Kea, Hawaii

NASA Astrophysics Data System (ADS)

Marin, N.; Farmer, J. D.; Zacny, K.; Sellar, R. G.; Nunez, J.

2011-12-01

This study seeks to understand variations in composition and texture of basaltic pyroclastic materials used in the 2010 International Lunar Surface Operation-In-Situ Resource Utilization Analogue Test (ILSO-ISRU) held on the slopes of Mauna Kea Volcano, Hawaii (1). The quantity and quality of resources delivered by ISRU depends upon the nature of the materials processed (2). We obtained a one-meter deep auger cuttings sample of a basaltic regolith at the primary site for feed stock materials being mined for the ISRU field test. The auger sample was subdivided into six, ~16 cm depth increments and each interval was sampled and characterized in the field using the Multispectral Microscopic Imager (MMI; 3) and a portable X-ray Diffractometer (Terra, InXitu Instruments, Inc.). Splits from each sampled interval were returned to the lab and analyzed using more definitive methods, including high resolution Powder X-ray Diffraction and Thermal Infrared (TIR) spectroscopy. The mineralogy and microtexture (grain size, sorting, roundness and sphericity) of the auger samples were determined using petrographic point count measurements obtained from grain-mount thin sections. NIH Image J (http://rsb.info.nih.gov/ij/) was applied to digital images of thin sections to document changes in particle size with depth. Results from TIR showed a general predominance of volcanic glass, along with plagioclase, olivine, and clinopyroxene. In addition, thin section and XRPD analyses showed a down core increase in the abundance of hydrated iron oxides (as in situ weathering products). Quantitative point count analyses confirmed the abundance of volcanic glass in samples, but also revealed olivine and pyroxene to be minor components, that decreased in abundance with depth. Furthermore, point count and XRD analyses showed a decrease in magnetite and ilmenite with depth, accompanied by an increase in Fe3+phases, including hematite and ferrihydrite. Image J particle analysis showed that the average grain size decreased down the depth profile. This decrease in average grain size and increase in hydrated iron oxides down hole suggests that the most favorable ISRU feedstock materials were sampled in the lower half-meter of the mine section sampled.

Shock metamorphism of ordinary chondrites

NASA Technical Reports Server (NTRS)

Stoeffler, Dieter; Keil, Klaus; Scott, Edward R. D.

1991-01-01

This study proposes a revised petrographic classification of progressive stages of shock metamorphism of 26 ordinary chondrites. Six stages of shock (S1 to S6) are defined on the basis of shock effects in olivine and plagioclase as recognized by thin section microscopy, and the characteristic shock effects of each shock stage are described. It is concluded that shock effects and the sequence of progressively increasing degrees of shock metamorphosis are very similar in H, L, and LL groups. Differences in the frequency distribution of shock stages are relatively minor. It is suggested that the collisional histories of the H, L, and LL parent bodies were similar. Petrologic type-3 chondrites are deficient in stages S4 and S6 and, with increasing petrologic type, the frequency of stages S4 to S6 increases. It is suggested that the more porous and volatile-rich Type-3 chondrites are subject to melting at a lower shock pressure than the nonporous chondrites of higher petrologic type. Stage S3 is the most abundant in nearly all petrologic types.

Reverse engineering the physical chemistry of making Egyptian faience through compositional analysis of the cementation process

NASA Astrophysics Data System (ADS)

Pourattar, Parisa

The cementation process of making Egyptian faience, reported by Hans Wulff from a workshop in Qom, Iran, has not been easy to replicate and various views have been set forth to understand the transport of materials from the glazing powder to the surfaces of the crushed quartz beads. Replications of the process fired to 950° C and under-fired to 850° C were characterized by electron beam microprobe analysis (EPMA), petrographic thin section analysis, and scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDS). Chemical variations were modeled using thermal data, phase diagrams, and copper vaporization experiments. These replications were compared to 52 examples from various collections, including 20th century ethnographic collections of beads, glazing powder and plant ash, 12th century CE beads and glazing powder from Fustat (Old Cairo), Egypt, and to an earlier example from Abydos, Egypt in the New Kingdom and to an ash example from the Smithsonian Institution National Museum of Natural History.

Algal blooms and "Marine snow": Mechanisms that enhance preservation of organic carbon in ancient fine-grained sediments

USGS Publications Warehouse

Macquaker, Joe H.S.; Keller, Margaret A.; Davies, Sarah J.

2010-01-01

Combined petrographic and geochemical methods are used to investigate the microfabrics present in thin sections prepared from representative organic carbon-rich mudstones collected from three successions (the Kimmeridge Clay Formation, the Jet Rock Member of the Whitby Mudstone Formation, and the pebble shale and Hue Shale). This study was initiated to determine how organic carbon-rich materials were being delivered to the sediment–water interface, and what happened to them after deposition, prior to deep burial.Analyses of the fabrics present shows that they exhibit many common attributes. In particular they are all: (1) highly heterogeneous on the scale of a thin section, (2) organized into thin beds (< 10 mm thick) composed mainly of mineral mixtures of fine-grained siliciclastic detritus and carbonate materials, and (3) contain significant concentrations of organic carbon, much of which is organized into laminasets that contain abundant organomineralic aggregates and pellets. In addition, framboidal pyrite (range of sizes from < 20 μm to < 1 μm) and abundant agglutinated foraminifers are present in some units. The individual beds are commonly sharp-based and overlain by thin, silt lags. The tops of many of the beds have been homogenized and some regions of the pelleted laminasets contain small horizontal burrows.The organomineralic aggregates present in these mudstones are interpreted to be ancient examples of marine snow. This marine snow likely formed in the water column, particularly during phytoplankton blooms, and was then transported rapidly to the seafloor. The existence of the thin beds with homogenized tops and an in-situ infauna indicates that between blooms there was sufficient oxygen and time for a mixed layer to develop as a result of sediment colonization by diminutive organisms using either aerobic or dysaerobic metabolic pathways. These textures suggest that the constituents of these mudstones were delivered neither as a continuous rain of sediment nor were the bottom waters persistently anoxic. In addition, the presence of thin lags and sharp-based beds suggests that the seafloor was being episodically reworked during deposition. These fabrics indicate that conditions in the water columns and at the seafloors while these rocks were being deposited were very dynamic, and episodic fluxes of high concentrations of organic carbon to the seafloor, during phytoplankton blooms, likely enhanced preservation of organic carbon.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

1992-06-01

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

QACD: A method for the quantitative assessment of compositional distribution in geologic materials

NASA Astrophysics Data System (ADS)

Loocke, M. P.; Lissenberg, J. C. J.; MacLeod, C. J.

2017-12-01

In order to fully understand the petrogenetic history of a rock, it is critical to obtain a thorough characterization of the chemical and textural relationships of its mineral constituents. Element mapping combines the microanalytical techniques that allow for the analysis of major- and minor elements at high spatial resolutions (e.g., electron microbeam analysis) with 2D mapping of samples in order to provide unprecedented detail regarding the growth histories and compositional distributions of minerals within a sample. We present a method for the acquisition and processing of large area X-ray element maps obtained by energy-dispersive X-ray spectrometer (EDS) to produce a quantitative assessment of compositional distribution (QACD) of mineral populations within geologic materials. By optimizing the conditions at which the EDS X-ray element maps are acquired, we are able to obtain full thin section quantitative element maps for most major elements in relatively short amounts of time. Such maps can be used to not only accurately identify all phases and calculate mineral modes for a sample (e.g., a petrographic thin section), but, critically, enable a complete quantitative assessment of their compositions. The QACD method has been incorporated into a python-based, easy-to-use graphical user interface (GUI) called Quack. The Quack software facilitates the generation of mineral modes, element and molar ratio maps and the quantification of full-sample compositional distributions. The open-source nature of the Quack software provides a versatile platform which can be easily adapted and modified to suit the needs of the user.

Petrographic and geochemical characteristics of a section through the Tiva Canyon Tuff at Antler Ridge, Yucca Mountain, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, F.R.; Widmann, B.L.; Dickerson, R.P.

1994-12-31

The Tiva Canyon Tuff of the Paintbrush Group of Miocene age caps much of Yucca Mountain, Nevada and is a compositionally zoned, compound cooling, pyroclastic flow that ranges from a dominantly high-silica rhyolitic base to a quartz-latitic caprock. Petrographic and geochemical studies have focused on rigorously defining the internal stratigraphy of this unit to support the detailed mapping of the Ghost Dance fault and other structures in the central fault block of Yucca Mountain. This study shows that devitrification textures and vapor phase mineralogy, in addition to other physical attributes such as pumice variability (flattening) and crystal content, can bemore » used as distinguishing criteria to better define lithologic zones within the Tiva Canyon Tuff. In addition, the study also shows that the petrographic textures and chemistry of the groundmass vary systematically within recognizable lithologic zones and may be used to characterize and vertically divide litho-stratigraphic zones within the Tiva Canyon Tuff.« less

Lithological and Petrographic Analyses of Carbonates and Sandstones From the Southern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Garcia-Avendaño, A.; Urrutia-Fucugauchi, J.

2012-04-01

We present results of sedimentological and petrological studies of drill cores from the Bay of Campeche in the southern Gulf of Mexico. Based on reports on drill cores obtained from oil exploratory wells in the Cantarell Complex located 80 kilometres offshore in the Bay of Campeche and studies related to regional geology composite simplified stratigraphic columns for offshore Campeche region have been constructed up to depths of approximately 5000 m. The stratigraphic column is formed by a thick sediment sequence of Middle Jurassic age (evaporites, Callovian), Late Jurassic (terrigenous, calcareous clays and calcareous layers), Lower Cretaceous (carbonates), Upper Cretaceous-Paleogene (calcareous breccias), Paleogene-Neogene (terrigenous-carbonates intercalations) and Quaternary (terrigenous). The core samples studied come from wells in the Sihil and Akal fields in Cantarell. Analysis of reports on lithological descriptions indicates that these wells sample dolomitized sedimentary breccias from the Upper Cretaceous-Paleocene and fine-grained sandstones from the Late Jurassic Tithonian, respectively. Based on results of petrographic studies, the texture, cementing material and porosity of the units have been documented. The thin sections for carbonates were classified based on their texture according to Dunham (1962) for carbonate rocks, classified according to their components using the ternary diagrams of Folk (1974). Percentages refer to the data presented in tables, which were obtained by point-counting technique (with a total 250). Photomicrographs of scanning electron microscope (SEM) provide magnification for easy documentation of crystalline arrangements and description of micro-porous for different types of carbonates such as dolomite, in addition to the morphology of authigenic clays. Results of these studies and previous works in the area permit characterization of diagenetic processes of the carbonate sediments in the Campeche Bay, and provide information related to oil maturation, storage and potential flow in the Cantarell reservoirs.

Magma Mingling of Multiple Mush Magmas

NASA Astrophysics Data System (ADS)

Graham, B.; Leitch, A.; Dunning, G.

2016-12-01

This field, petrographic, and geochemical study catalogues complicated magma mingling at the field to thin section scale, and models the emplacement of multiple crystal-rich pulses into a growing magma chamber. Modern theories present magma chambers as short-lived reservoirs that are continuously fed by intermittent magma pulses and suggest processes that occur within them can be highly dynamic. Differences in the rheology of two mingling magmas, largely affected by crystallinity, can result in varied textural features that can be preserved in igneous rocks. Field evidence of complex magma mingling is observed at Wild Cove, located along the northeast shoreline of Fogo Island, Newfoundland, an area interpreted to represent the roof/wall region of the Devonian Fogo Batholith. Fine-grained intermediate enclaves are contained in host rocks of similar composition and occur in round to amoeboid shapes. Dykes of similar composition are also observed near enclaves suggesting they were broken up into globules in localized areas. These provide evidence for a possible mechanism by which enclaves were formed as dykes passed through a more liquid-rich region of the magma chamber. The irregular but sharp nature of the boundaries between units suggest that all co-existed as "mushy" magmas with variable crystallinities reflecting a wide range in temperature between their respective liquidus and solidus. Textural evidence of complex mingling between mush units includes the intrusion of tonalite dykes into quartz diorite and granite mushes. The dykes were later pulled apart and subsequently back-intruded by liquid from the host mush (Figure). Observed magmatic tubes of intermediate magma cross-cutting through magma of near identical composition likely reflect compaction of the underlying mush after intrusion of new pulses of magma into the system. Petrographic examination of contacts between units reveals that few are chilled and medium to coarse grained boundaries are the norm.

Influence of mineralogical, petrographical, and geochemical characteristics of impure limestones on the composition of fired hydraulic lime: a case study on Lower Palaeozoic limestones from the Prague Basin (Barrandian area, Czech Republic)

NASA Astrophysics Data System (ADS)

Kozlovcev, Petr; Přikryl, Richard

2014-05-01

Prague Basin, making part of the Barrandian area (Bohemian Massif, Czech Republic), is a rift-like depression filled with non-metamorphosed sedimentary series of Upper Proterozoic - Lower Palaeozoic age. Among other sedimentary rocks, different types of limestones are present. These limestone were historically exploited and used for various purposes including natural and decorative stone, common construction material, and also a raw material for firing of inorganic binders: aerial lime, hydraulic lime and/or, more recently, Ordinary Portland Cement (OPC). Lithotypes with higher amount of silica and/or clay component were of special interest due to the hydraulicity of fired product known as "pasta di Praga" in Baroque. However, our recent knowledge of these limestones is incomplete in terms of the contribution of mineralogical, geochemical, and petrographical characteristics on the properties of fired hydraulic lime. In the recent study, representative samples of 4 facies of the Lower Devonian limestone (Kosoř ls., Řeporyje ls., Dvorce-Prokop ls., and Zlíchov ls.) were subjected to a detailed mineralogical and petrographic study of raw material by means of polarizing microscopy, cathodoluminiscence of thin sections and scanning electron microscopy with an energy dispersive spectrometer (SEM-EDS). X-ray diffraction (XRD) of insoluble residues obtained by treatment with both the hydrochloric acid and the acetic acid solution was used. Wet silicate analysis provided data on the content of major elements from which standard cement and lime indexes and modules were calculated. Laboratory firing experiments of these limestone were performed by a calcination at temperature ranging from 850 to 1200°C (after 50°C). XRD of fired products shows that limestones with high content of silica (some of the Dvorce-Prokop ls.) produced binder with high amount of newly formed calcium silicates (larnite). Gehlenite and others calcium aluminates and aluminosilicates are typical for firing of limestones with higher content of clay minerals (illite and kaolinite) which are common in Kosoř ls., Řeporyje ls., and Dvorce-Prokop ls. Brownmillerite was formed in limestones exhibiting higher proportion of Fe-oxihydroxides (specifically Řeporyje ls). Presence of free lime and portlandite correlates with decreasing content of non-carbonate material (some varieties of the Dvorce-Prokop ls. from Bráník Rocks).

Rapid Determination of Mineral Abundance by X-ray Microfluorescence Mapping and Multispectral Image Analysis

NASA Astrophysics Data System (ADS)

Moscati, R. J.; Marshall, B. D.

2005-12-01

X-ray microfluorescence (XRMF) spectrometry is a rapid, accurate technique to map element abundances of rock surfaces (such as thin-section billets, the block remaining when a thin section is prepared). Scanning a specimen with a collimated primary X-ray beam (100 μm diameter) generates characteristic secondary X-rays that yield the relative chemical abundances for the major rock-/mineral-forming analytes (such as Si, Al, K, Ca, and Fe). When Cu-rich epoxy is used to impregnate billets, XRMF also can determine porosity from the Cu abundance. Common billet scan size is 30 x 15 mm and the typical mapping time rarely exceeds 2.5 hrs (much faster than traditional point-counting). No polishing or coating is required for the billets, although removing coarse striations or gross irregularities on billet surfaces should improve the spatial accuracy of the maps. Background counts, spectral artifacts, and diffraction peaks typically are inconsequential for maps of major elements. An operational check is performed after every 10 analyses on a standard that contains precisely measured areas of Mn and Mo. Reproducibility of the calculated area ratio of Mn:Mo is consistently within 5% of the known value. For each billet, the single element maps (TIFF files) generated by XRMF are imported into MultiSpec© (a program developed at Purdue University for analysis of multispectral image data, available from http://dynamo.ecn.purdue.edu/~biehl/MultiSpec/) where mineral phases can be spectrally identified and their relative abundances quantified. The element maps for each billet are layered to produce a multi-element file for mineral classification and statistical processing, including modal estimates of mineral abundance. Although mineral identification is possible even if the mineralogy is unknown, prior petrographic examination of the corresponding thin section yields more accurate maps because the software can be set to identify all similar pixels. Caution is needed when using MultiSpec© to distinguish mineral phases with similar chemistry (for example, opal and quartz) and minerals that occupy very small surface areas (<10 pixels). In either case, careful petrography and informed use of the software will allow rapid use of MultiSpec© to create accurate mineral maps of rock and thin-section billet surfaces. This technique, for example, has allowed quantitative estimates of calcite and silica abundances to be determined on about 200 samples of secondary mineral coatings from the unsaturated zone at Yucca Mountain, Nevada.

Role of lichens in weathering of granodiorite in the Sila uplands (Calabria, southern Italy)

NASA Astrophysics Data System (ADS)

Scarciglia, Fabio; Saporito, Natalina; La Russa, Mauro F.; Le Pera, Emilia; Macchione, Maria; Puntillo, Domenico; Crisci, Gino M.; Pezzino, Antonino

2012-12-01

This paper explores the role of five recurrent epilithic lichen species (Aspicilia intermutans (Nyl.) Arnold, Xanthoparmelia pulla (Ach.) O. Blanco, A. Crespo, Elix, D. Hawksw. & Lumbsch, Rhizocarpon lecanorinum Anders, Tephromela atra (Huds.) Hafellner and Lecanora bolcana (Pollini) Poelt), which encrust granodiorite spheroidal boulders exposed in the Sila uplands (Calabria, southern Italy), in weathering of plutonic rocks in a typical mountainous Mediterranean environment. A detailed investigation was carried out on the lichen-rock interface of each species, by comparing them mutually and with lichen-free granodiorite samples. For this purpose, the lichen species were sampled together with the encrusted rock surface for detailed mineral-petrographic analyses performed in thin and ultra-thin sections. Optical and scanning electron microscopy of these sections and of bulk samples permitted us to highlight the peculiar modes of physical and chemical attacks of lichen thalli and hyphae on and into the substratum for each species. Crack systems often parallel to the outer rock surface appear often intruded by hyphae, which cause rupture of primary minerals, with detachment and progressive incorporation of their fragments into the thallus. In particular, the species L. bolcana and T. atra revealed an unexpected, partly endolithic behavior, presumably enhanced by the presence of rock fractures earlier generated by other physical breakage processes already affecting the spheroidal boulders in the Sila mountains. Dissolution features often affect primary minerals (even quartz), that may show very peculiar patterns which are suggestive of a biologically-induced control. Various phyllosilicate clay minerals were identified using SEM-EDS microprobe analyses and FT-IR spectroscopy, which also enabled the identification of possible amorphous silica (or quartz micrograins), rhizocarpic acid and carotenoid at the encrusted granodiorite interface. In contrast, neither oxalic acids nor oxalates were detected.

Eucrite Impact Melt NWA 5218 - Evidence for a Large Crater on Vesta

NASA Technical Reports Server (NTRS)

Wittmann, Axel; Hiroi, Takahiro; Ross, Daniel K.; Herrin, Jason S.; Rumble, Douglas, III; Kring, David A.

2011-01-01

Northwest Africa (NWA) 5218 is a 76 g achondrite that is classified as a eucrite [1]. However, an initial classification [2] describes it as a "eucrite shock-melt breccia...(in which) large, partially melted cumulate basalt clasts are set in a shock melt flow...". We explore the petrology of this clast-bearing impact melt rock (Fig. 1), which could be a characteristic lithology at large impact craters on asteroid Vesta [3]. Methods: Optical microscopy, scanning electronmicroscopy, and Raman spectroscopy were used on a thin section (Fig. 1) for petrographic characterization. The impact melt composition was determined by 20 m diameter defocused-beam analyses with a Cameca SX-100 electron microprobe. The data from 97 spots were corrected for mineral density effects [4]. Constituent mineral phases were analyzed with a focusedbeam. Bidirectonal visible and near-infrared (VNIR) and biconical FT-IR reflectance spectra were measured on the surface of a sample slab on its central melt area and on an eucrite clast, and from 125-500 m and <125 m powders of melt. Results: General petrography: The sample specimen is a coherent, medium dark-grey (N4), melt rock. The thin section captures a central, subophitic-textured melt that contains 1 cm to tens of m-size subangular to rounded, variably-shocked eucrite clasts. Clasts >100 m are coarse-grained with equigranular 1 mm size plagioclase, quartz, and clinopyroxene (Fig. 1). Single crystals of chromite, ilmenite, zircon, Ca-Mg phosphate, Fe-metal, and troilite are embedded in the melt. Polymineralic clasts are mostly compositionally similar to the above mentioned larger clasts but scarce granulitic fragments are observed as well.

Conodont biostratigraphy from the upper San Juan Formation (Middle Ordovician) at Niquivil, Argentine Precordillera

NASA Astrophysics Data System (ADS)

Mango, M. J.; Albanesi, G. L.

2018-07-01

The present work deals with the conodont biostratigraphy from the upper San Juan Formation in the section of Niquivil, Central Precodillera of San Juan, Argentina. We study the upper 129.45 m of the San Juan Formation, starting from the upper strata of the second reef horizon up to the top of the formation. Digested limestone samples yielded 20 conodont species. The presence of Tripodus laevis Bradshaw not associated to Baltoniodus navis (Lindström) allows the recognition of the Baltoniodus triangularis-Tripodus laevis Zone, which is interpreted as correlative with the "Parapanderodus" nogamii/Parapanderodus gracilis/Ansella jemtlandica Association of Lehnert (1993, 1995; Lehnert and Keller, 1993), conversely to previous interpretations that suggested the latter as correlative to the Baltoniodus navis Zone. The zonal identification is supported by the associated conodonts Protopanderodus rectus (Lindström), Juanognathus jaanussoni Serpagli, Juanognathus n. sp., Protopanderodus gradatus (Serpagli), Rossodus barnesi Albanesi, Paltodus subaequalis Pander, Drepanodus arcuatus (Pander), Cornuodus longibasis (Lindström), Protopanderodus elongatus Serpagli, Oistodus lanceolatus Pander, Periodon flabellum (Lindström), Semiacontiodus potrerillensis Albanesi, Triangulodus brevibasis (Sergeeva), Paroistodus originalis (Sergeeva), Drepanoistodus forceps (Lindström), Oistodus multicorrugatus Harris, Parapanderodus paracornuformis (Ethington and Clark), Anodontus longus Stouge and Bagnoli, and Pteracontiodus cryptodens Mound. The petrographic microscope analysis of carbonate rocks thin sections refer to proximal middle ramp deposits.

Seaching for a Silver Lining: Using Pb Isotopes to Constrain the Source of Argentiferous Galena at La Isabela

NASA Astrophysics Data System (ADS)

Thibodeau, A. M.; Killick, D. J.; Ruiz, J.; Chesley, J. T.; Baker, M.

2005-12-01

This study investigates the smelting and refining of argentiferous galena at La Isabela, Dominican Republic (1493-1498), the town founded by Columbus on his second voyage to the Americas. Archaeologists recovered approximately 100 kilograms of galena and 200 kilograms of metallurgical slag near the remains of a crude furnace unearthed at the site (Deagan and Cruxent 2002). The purpose of this study was to determine if these remains are evidence that members of Columbus's fleet prospected for silver during his second expedition. Samples of ore and slag were examined as metallographic polished sections, and petrographic thin sections by optical and scanning electron microscopes. The composition of the ore and slag allows us to infer these ores were processed in a two-stage procedure to produce silver metal and a lead silicate slag. Electron microprobe analysis of galena indicates highly variable but low Ag content (50 ppm), which may account for the fact some of the ore was left unprocessed. Lead isotope analysis by multi-collector ICP-MS indicates that the galena likely came from a single source and was not mined within the Caribbean. Instead, the isotopic signature of these ores is consistent with an Old World source, possibly in the Linares-La Carolina Pb-Zn vein field of southwestern Spain.

Petrography of isotopically-dated clasts in the Kapoeta howardite and petrologic constraints on the evolution of its parent body

NASA Technical Reports Server (NTRS)

Dymek, R. F.; Albee, A. L.; Chodos, A. A.; Wasserburg, G. J.

1976-01-01

Results are presented for petrographic and electron microprobe studies of the isotopically dated A, B, C, and rho basaltic rock fragments separated from the howardite Kapoeta. Other lithic clasts and numerous mineral fragments in thin sections of Kapoeta are investigated in order to outline the range in lithology and chemistry of the source materials from which the Kapoeta meteorite is derived. The data obtained are compared to those from other meteorite and lunar samples, with particular reference to the observational consequences for the evolution of the Kapoeta parent body. A major conclusion is that there is no clearcut evidence for young magmatism on the Kapoeta parent body. The observations preclude the interpretation that the Kapoeta is a simple mixture of eucrites and diogenites. In contrast to the moon, a source of anorthositic rocks does not appear to have been present on the Kapoeta parent body which involved chiefly pyroxene. The FeO-MnO relationships suggest that the source of the materials in the Kapoeta parent planet are fundamentally related.

Green glass vitrophyre 78526 - An impact of very low-Ti mare basalt composition

NASA Technical Reports Server (NTRS)

Warner, R. D.; Taylor, G. J.; Kiel, K.; Planner, H. H.; Nehru, C. E.; Ma, M.-S.; Schmitt, R. A.

1978-01-01

Rake sample 78526 is an 8.77 g rock consisting primarily of vitrophyric pale green glass with subordinate mineral and lithic relics. Petrographic and compositional evidence leads to the following conclusions: (1) the bulk composition represents that of a mixture formed by impact melting of at least two different textural and compositional varieties of VLT mare basalt that are now present in the rock as lithic relics and a poorly defined low-Ti mare basalt component observed in thin section only in the form of isolated mineral relics; (2) the admixed VLT mare basalts had REE abundances lower than those found in other mare basalts (but probably higher than emerald green glass) and REE patterns showing significant enrichment of the heavy relative to light REE's, suggesting that they were derived by comparatively high degrees of partial melting of a clinopyroxene-rich source region; and (3) the impact melt supercooled to produce the vitrophyre, with rather sharply contrasting textural domains present in the vitrophyre resulting from differences in nucleation kinetics and degrees of supercooling in various portions of the sample.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durocher, S.; Al-Aasm, I.S.

1997-06-01

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

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada

USGS Publications Warehouse

du Bray, Edward A.; John, David A.; Box, Stephen E.; Vikre, Peter G.; Fleck, Robert J.; Cousens, Brian L.

2013-04-23

Petrographic and geochemical data for Cenozoic volcanic rocks of the Bodie Hills, California and Nevada // // This report presents petrographic and geochemical data for samples collected during investigations of Tertiary volcanism in the Bodie Hills of California and Nevada. Igneous rocks in the area are principally 15–6 Ma subduction-related volcanic rocks of the Bodie Hills volcanic field but also include 3.9–0.1 Ma rocks of the bimodal, post-subduction Aurora volcanic field. Limited petrographic results for local basement rocks, including Mesozoic granitoid rocks and their metamorphic host rocks, are also included in the compilation. The petrographic data include visual estimates of phenocryst abundances as well as other diagnostic petrographic criteria. The geochemical data include whole-rock major oxide and trace element data, as well as limited whole-rock isotopic data.

Petrographic methods of examining hardened concrete : a petrographic manual.

DOT National Transportation Integrated Search

1997-11-01

This manual was undertaken to record for all persons wishing to do concrete : petrography the petrographic procedures that have been found useful at the : Virginia Transportation Research Council. The manual is made up of an : introduction and chapte...

Lunar resources: Oxygen from rocks and soil

NASA Technical Reports Server (NTRS)

Allen, C. C.; Gibson, M. A.; Knudsen, C. W.; Kanamori, H.; Morris, R. V.; Keller, L. P.; Mckay, D. S.

1992-01-01

The first set of hydrogen reduction experiments to use actual lunar material was recently completed. The sample, 70035, is a coarse-grained vesicular basalt containing 18.46 wt. percent FeO and 12.97 wt. percent TiO2. The mineralogy includes pyroxene, ilmenite, plagioclase, and minor olivine. The sample was crushed to a grain size of less than 500 microns. The crushed basalt was reduced with hydrogen in seven tests at temperatures of 900-1050 C and pressures of 1-10 atm for 30-60 minutes. A capacitance probe, measuring the dew point of the gas stream, was used to follow reaction progress. Experiments were also conducted using a terrestrial basalt similar to some lunar mare samples. Minnesota Lunar Simulant (MLS-1) contains 13.29 wt. percent FeO, 2.96 wt. percent Fe2O3, and 6.56 wt. percent TiO2. The major minerals include plagioclase, pyroxene, olivine, ilmenite, and magnetite. The rock was ground and seived, and experiments were run on the less than 74- and 500-1168-micron fractions. Experiments were also conducted on less than 74-micron powders of olivine, pyroxene, synthetic ilmenite, and TiO2. The terrestrial rock and mineral samples were reduced with flowing hydrogen at 1100 C in a microbalance furnace, with reaction progress monitored by weight loss. Experiments were run at atmospheric pressure for durations of 3-4 hr. Solid samples from both sets of experiments were analyzed by Mossbauer spectroscopy, petrographic microscopy, scanning electron microscopy, tunneling electron microscopy, and x-ray diffraction. Apollo 17 soil 78221 was examined for evidence of natural reduction in the lunar environment. This sample was chosen based on its high maturity level (I sub s/FeO = 93.0). The FeO content is 11.68 wt. percent and the TiO2 content is 3.84 wt. percent. A polished thin section of the 90-150 micron size fraction was analyzed by petrographic microscopy and scanning electron microscopy.

Pieces of Other Worlds - Extraterrestrial Samples for Education and Public Outreach

NASA Technical Reports Server (NTRS)

Allen, Carlton C.

2010-01-01

During the Year of the Solar System spacecraft from NASA and our international partners will encounter two comets; orbit the asteroid Vesta, continue to explore Mars with rovers, and launch robotic explorers to the Moon and Mars. We have pieces of all these worlds in our laboratories, and their continued study provides incredibly valuable "ground truth" to complement space exploration missions. Extensive information about these unique materials, as well as actual lunar samples and meteorites, are available for display and education. The Johnson Space Center (JSC) has the unique responsibility to curate NASA's extraterrestrial samples from past and future missions. Curation includes documentation, preservation, preparation, and distribution of samples for research, education, and public outreach. At the current time JSC curates six types of extraterrestrial samples: (1) Moon rocks and soils collected by the Apollo astronauts (2) Meteorites collected on US expeditions to Antarctica (including rocks from the Moon, Mars, and many asteroids including Vesta) (3) "Cosmic dust" (asteroid and comet particles) collected by high-altitude aircraft (4) Solar wind atoms collected by the Genesis spacecraft (5) Comet particles collected by the Stardust spacecraft (6) Interstellar dust particles collected by the Stardust spacecraft These rocks, soils, dust particles, and atoms continue to be studied intensively by scientists around the world. Descriptions of the samples, research results, thousands of photographs, and information on how to request research samples are on the JSC Curation website: http://curator.jsc.nasa.gov/ NASA provides a limited number of Moon rock samples for either short-term or long-term displays at museums, planetariums, expositions, and professional events that are open to the public. The JSC Public Affairs Office handles requests for such display samples. Requestors should apply in writing to Mr. Louis Parker, JSC Exhibits Manager. Mr. Parker will advise successful applicants regarding provisions for receipt, display, and return of the samples. All loans will be preceded by a signed loan agreement executed between NASA and the requestor's organization. Email address: louis.a.parker@nasa.gov Sets of twelve thin sections of Apollo lunar samples and sets of twelve thin sections of meteorites are available for short-term loan from JSC Curation. The thin sections are designed for use in college and university courses where petrographic microscopes are available for viewing. Requestors should contact the Ms. Mary Luckey, Education Sample Curator. Email address: mary.k.luckey@nasa.gov

Burdigalian turbid water patch reef environment revealed by larger benthic foraminifera

NASA Astrophysics Data System (ADS)

Novak, V.; Renema, W.; Throughflow-project

2012-04-01

Ancient isolated patch reefs outcropping from siliciclastic sediments are a trademark for the Miocene carbonate deposits occurring in East Kalimantan, Indonesia. They develop in transitional shelf sediments deposited between deltaic and deep marine deposits (Allen and Chambers, 1998). The Batu Putih Limestone (Wilson, 2005) and similar outcrops in adjacent areas have been characterized as shallow water carbonates influenced by high siliciclastic input, showing low relief patch reefs in turbid waters. Larger benthic foraminifera (LBF) are excellent markers for biochronology and paleoenvironmental reconstruction. This study aims to reveal age and paleoenvironment of a shallow water carbonate patch reef developed in mixed depositional system by using LBF and microfacies analysis. The studied section is located near Bontang, East Kalimantan, and is approximately 80 m long and 12 m high. It is placed within Miocene sediments in the central part of the Kutai Basin. Patch reef and capping sediments were logged through eight transects along section and divided into nine different lithological units from which samples were collected. Thin sections and isolated specimens of larger benthic foraminifera were analyzed and recognized to species level (where possible) providing age and environmental information. Microfacies analysis of thin sections included carbonate classification (textural scheme of Dunham, 1962) and assemblage composition of LBF, algae and corals relative abundance. Three environmentally indicative groups of LBF were separated based on test morphology, habitat or living relatives (Hallock and Glenn, 1986). Analysed foraminifera assemblage suggests Burdigalian age (Tf1). With use of microfacies analysis nine successive lithological units were grouped into five facies types. Paleoenvironmental reconstruction of LBF fossil assemblage indicate two cycles of possible deepening recorded in the section. Based on high muddy matrix ratio in analyzed thin-sections we still cannot conclude whether they were deeper water assemblage, or that they occurred in shallower water and influenced by turbid conditions as the result of terrigenous input. According to preliminary analysis and siliciclastic content in the sediments the later one should be more likely. Further work will include additional fossil groups analysis (corals, algae and bryozoans), detailed petrographical analysis and Strontium isotope stratigraphy. Allen, G.P., and Chambers, J.L.C. (1998): Sedimentation in the Modern and Miocene Mahakam Delta. Indonesian Petroleum Association, Jakarta, Indonesia, 236 p. Dunham, R.J. (1962): Classification of carbonate rocks according to their depositional texture. In: Ham, W.E., ed., Classification of Carbonate Rocks: American Association of Petroleum Geologists Memoir, v. 1, p. 108-121. Hallock, P. and Glenn, C.E. (1986): Larger Foraminifera: A tool for paleoenvironmental analysis of Cenozoic carbonate depositional facies. Palaios 1, 55-64. Wilson, M.E.J. (2005): Development of equatorial delta-front patch reefs during the Neogene, Borneo. - Journal of Sedimentary Research, 75(1): 114-133.

Petrographic manual : petrographic methods of examining hardened concrete, including introduction, sample preparation, questions and suggestions, and reading list.

DOT National Transportation Integrated Search

1991-01-01

This manual was undertaken to record for all persons wishing to do concrete petrography the petrographic procedures that have been found useful here at the Virginia Transportation Research Council. This interim report is made up of the introduction, ...

Use of geochemical mass balance modelling to evaluate the role of weathering in determining stream chemistry in five mid-Atlantic watersheds on different lithologies

USGS Publications Warehouse

O'Brien, Anne K.; Rice, Karen C.; Bricker, Owen P.; Kennedy, Margaret M.; Anderson, R. Todd

1997-01-01

The importance of mineral weathering was assessed and compared for five mid-Atlantic watersheds receiving similar atmospheric inputs but underlain by differing bedrock. Annual solute mass balances and volume-weighted mean solute concentrations were calculated for each watershed for each year of record. In addition, primary and secondary mineralogy were determined for each of the watersheds through analysis of soil samples and thin sections using petrographic, scanning electron microscope, electron microprobe and X-ray diffraction techniques. Mineralogical data were also compiled from the literature. These data were input to NETPATH, a geochemical program that calculates the masses of minerals that react with precipitation to produce stream water chemistry. The feasibilities of the weathering scenarios calculated by NETPATH were evaluated based on relative abundances and reactivities of minerals in the watershed. In watersheds underlain by reactive bedrocks, weathering reactions explained the stream base cation loading. In the acid-sensitive watersheds on unreactive bedrock, calculated weathering scenarios were not consistent with the abundance of reactive minerals in the underlying bedrock, and alternative sources of base cations are discussed.

Microdeformation in Vredefort rocks; evidence for shock metamorphism

NASA Technical Reports Server (NTRS)

Reimold, W. U.; Andreoli, M. A. G.; Hart, R. J.

1988-01-01

Planar microdeformations in quartz from basement or collar rocks of the Vredefort Dome have been cited for years as the main microtextural evidence for shock metamorphism in this structure. In addition, Schreyer describes feldspar recrystallization in rocks from the center of the Dome as the result of transformation of diaplectic glass, and Lilly reported the sighting of mosaicism in quartz. These textural observations are widely believed to indicate either an impact or an internally produced shock origin for the Vredefort Dome. Two types of (mostly sub) planar microdeformations are displayed in quartz grains from Vredefort rocks: (1) fluid inclusion trails, and (2) straight optical discontinuities that sometimes resemble lamellae. Both types occur as single features or as single or multiple sets in quartz grains. Besides qualitative descriptions of cleavage and recrystallization in feldspar and kinkbands in mica, no further microtextural evidence for shock metamorphism at Vredefort has been reported to date. Some 150 thin sections of Vredefort basement rocks were re-examined for potential shock and other deformation effects in all rock-forming minerals. This included petrographic study of two drill cores from the immediate vicinity of the center of the Dome. Observations recorded throughout the granitic core are given along with conclusions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

D`Agostino, A.E.; Jordan, D.W.; Jordan, D.W.

Shanmugam and Moiola (1995) put forth a new interpretation of sandstone depositional processes in the Jackfork Group exposed in the spillway at DeGray Lake, near Arkadelphia, Arkansas. Their novel interpretation of deposition dominated by sandy, matrix-supported debris flows is at odds with nearly every other investigation of the Jackfork to date. One key to their interpretation is their contention that the Jackfork sandstones have a high matrix content (as high as 25%). The high matrix content is critical to their arguments about the textural characteristics and flow properties of debris flows vs. turbidites. In our guidebook, we presented a largemore » volume of petrographic data collected from samples taken from the Jackfork exposed on the east and west sides of the Spillway at DeGray Lake (and other locations as well). D`Agostino performed nearly al of the petrographic analyses presented in that guidebook. We disagree strongly with the reinterpretations of Shanmugam and Moiola and believe we can confidently address issues of petrography and matrix content. Specifically, we wish to address four points: (1) the amount of petrographic sampling done by Shanmugam and Moiola (1995); i.e., sampling density in a 327-m- (1072-ft) thick section, (2) overall matrix content of Jackfork sandstones, and Shanmugam and Moiola`s misrepresentation of our data, plus their apparent unfamiliarity with pertinent published data on the petrography of the Jackfork, (3) the distinction among authigenic clay, density in a 327-m- (1072-ft-) thick section, (2) overall matrix content of Jackfork sandstones, and Shanmugam and Moiola`s misrepresentation of our data, plus their apparent unfamiliarity with pertinent published data on the petrography of the Jackfork, (3) the distinction among authigenic clay, detrital clay, and other matrix materials, which Shanmugam and Moiola do not adequately discuss, and (4) the relationship of matrix content to their own facies classification scheme.« less

Evidence for a composite organic–inorganic fabric of belemnite rostra: Implications for palaeoceanography and palaeoecology

DOE PAGES

Hoffmann, Rene; Richter, D. K.; Neuser, R. D.; ...

2016-06-11

Carbonate skeletons of fossil marine organisms are widely used to reconstruct palaeoceanographic parameters. Specifically, the geochemistry of Jurassic and Cretaceous belemnite rostra is traditionally interpreted to represent near sea-surface seawater properties. More recently, an increasing number of workers, have reported significant scatter in geochemical data (e.g., δ 18O, δ 13C, element/Ca ratio) when comparing rostra from the same stratigraphic level or within a single belemnite rostrum. This scatter is not explained by differential diagenetic overprint alone. Here we report petrographic evidence on the primary ultrastructure of rostra of Megateuthis (Middle Jurassic) and Belemnitella and Gonioteuthis (Late Cretaceous). The biogenic ultrastructuremore » consists of a filigree framework of triaxial branches and tetrahedrons of variable size forming a honeycomb-like network. Data presented here suggest that these rostra yielded as much as 50 to 90% primary pore space. On the level of a working hypothesis – and in analogy with modern cephalopods – we propose that the pore space was formerly filled with body fluid and/or organic compounds during the life time of these organisms. Intra-rostral porosity was post mortem occluded by earliest diagenetic isopachous calcite cements of a non-biogenic origin. These may have been precipitated due to increased alkalinity related to the decay of organic matter. If this holds true, then the resulting fabric represents a composite biogenic/abiogenic structure. In order to optically separate the two calcite phases forming a single calcite fibre, we employed a wide range of state-of-the-art analytical tools to thin sections and ultra-thin sections of well-preserved specimens. Finally, pending a verification of these well-supported ultrastructural data by means of high-resolution geochemical analyses from biogenic and abiogenic phases, we suggest that these findings have significance for those using belemnite rostra as archives of their palaeoenvironment.« less

Evidence for a composite organic-inorganic fabric of belemnite rostra: Implications for palaeoceanography and palaeoecology

NASA Astrophysics Data System (ADS)

Hoffmann, R.; Richter, D. K.; Neuser, R. D.; Jöns, N.; Linzmeier, B. J.; Lemanis, R. E.; Fusseis, F.; Xiao, X.; Immenhauser, A.

2016-07-01

Carbonate skeletons of fossil marine organisms are widely used to reconstruct palaeoceanographic parameters. Specifically, the geochemistry of Jurassic and Cretaceous belemnite rostra is traditionally interpreted to represent near sea-surface seawater properties. More recently, an increasing number of workers, have reported significant scatter in geochemical data (e.g., δ18O, δ13C, element/Ca ratio) when comparing rostra from the same stratigraphic level or within a single belemnite rostrum. This scatter is not explained by differential diagenetic overprint alone. Here we report petrographic evidence on the primary ultrastructure of rostra of Megateuthis (Middle Jurassic) and Belemnitella and Gonioteuthis (Late Cretaceous). The biogenic ultrastructure consists of a filigree framework of triaxial branches and tetrahedrons of variable size forming a honeycomb-like network. Data presented here suggest that these rostra yielded as much as 50 to 90% primary pore space. On the level of a working hypothesis - and in analogy with modern cephalopods - we propose that the pore space was formerly filled with body fluid and/or organic compounds during the life time of these organisms. Intra-rostral porosity was post mortem occluded by earliest diagenetic isopachous calcite cements of a non-biogenic origin. These may have been precipitated due to increased alkalinity related to the decay of organic matter. If this holds true, then the resulting fabric represents a composite biogenic/abiogenic structure. In order to optically separate the two calcite phases forming a single calcite fibre, we employed a wide range of state-of-the-art analytical tools to thin sections and ultra-thin sections of well-preserved specimens. Pending a verification of these well-supported ultrastructural data by means of high-resolution geochemical analyses from biogenic and abiogenic phases, we suggest that these findings have significance for those using belemnite rostra as archives of their palaeoenvironment.

Carbonate pore system evaluation using the velocity-porosity-pressure relationship, digital image analysis, and differential effective medium theory

NASA Astrophysics Data System (ADS)

Lima Neto, Irineu A.; Misságia, Roseane M.; Ceia, Marco A.; Archilha, Nathaly L.; Oliveira, Lucas C.

2014-11-01

Carbonate reservoirs exhibit heterogeneous pore systems and a wide variety of grain types, which affect the rock's elastic properties and the reservoir parameter relationships. To study the Albian carbonates in the Campos Basin, a methodology is proposed to predict the amount of microporosity and the representative aspect ratio of these inclusions. The method assumes three pore-space scales in two representative inclusion scenarios: 1) a macro-mesopore median aspect ratio from the thin-section digital image analysis (DIA) and 2) a microporosity aspect ratio predicted based on the measured P-wave velocities. Through a laboratory analysis of 10 grainstone core samples of the Albian age, the P- and S-wave velocities (Vp and Vs) are evaluated at effective pressures of 0-10 MPa. The analytical theories in the proposed methodology are functions of the aspect ratios from the differential effective medium (DEM) theory, the macro-mesopore system recognized from the DIA, the amount of microporosity determined by the difference between the porosities estimated from laboratorial helium-gas and the thin-section petrographic images, and the P-wave velocities under dry effective pressure conditions. The DIA procedure is applied to estimate the local and global parameters, and the textural implications concerning ultrasonic velocities and image resolution. The macro-mesopore inclusions contribute to stiffer rocks and higher velocities, whereas the microporosity inclusions contribute to softer rocks and lower velocities. We observe a high potential for this methodology, which uses the microporosity aspect ratio inverted from Vp to predict Vs with a good agreement. The results acceptably characterize the Albian grainstones. The representative macro-mesopore aspect ratio is 0.5, and the inverted microporosity aspect ratio ranges from 0.01 to 0.07. The effective pressure induced an effect of slight porosity reduction during the triaxial tests, mainly in the microporosity inclusions, slightly changing the amount and the aspect ratio of the microporosity.

Facies distribution, depositional environment, and petrophysical features of the Sharawra Formation, Old Qusaiba Village, Central Saudi Arabia

NASA Astrophysics Data System (ADS)

Abbas, Muhammad Asif; Kaminski, Michael; Umran Dogan, A.

2016-04-01

The Silurian Sharawra Formation has great importance as it rests over the richest source rock of the Qusaiba Formation in central Saudi Arabia. The Sharawra Formation has four members including Jarish, Khanafriyah, Nayyal, and Zubliyat. The formation mainly consists of sandstone and siltstone with subordinate shale sequences. The lack of published research on this formation requires fundamental studies that can lay the foundation for future research. Three outcrops were selected from the Old Qusaiba Village in Central Saudi Arabia for field observations, petrographical and petrophysical study. Thin section study has been aided by quantitative mineralogical characterization using scanning electron microscopy - energy dispersive spectroscopy and powder x-ray diffraction (XRD) for both minerals, cements, and clay minerals (detrital and authigenic). The outcrops were logged in detail and nine different lithofacies have been identified. The thin section study has revealed the Sharawra Formation to be mainly subarkosic, while the mica content increases near to its contact with the Qusaiba Formation. The XRD data has also revealed a prominent change in mineralogy with inclusion of minerals like phlogopite and microcline with depths. Field observations delineated a prominent thinning of strata as lithofacies correlation clearly shows the thinning of strata in the southwestern direction. The absence of outcrop exposures further supports the idea of southwestern thinning of strata. This is mainly attributed to local erosion and the presence of thicker shale interbeds in the southeastern section, which was probably subjected to more intense erosion than the northwestern one. The Sharawra Formation rests conformably over the thick transgressive shale sequence, deposited during the post glacial depositional cycle. The lowermost massive sandstone bed of the Sharawra Formation represents the beginning of the regressive period. The shale interbeds in the lower part are evidence of moderate-scale transgressive episodes, while the thin shale interbeds in the middle and upper part of the Sharawra Formation represent small-scale transgressions. Overall, the Sharawra Formation contains a series of repetitive transgressive and regressive events and has been interpreted as a pro-deltaic deposit in previous studies. In the present study, the lowermost sandstone thickly bedded facies lie within the transition zone environment. The siltstone facies and the horizontally stratified facies show a middle shore face environment. The middle shore face environment is present locally. The bioturbation in the uppermost facies is indicative of the upper shore face environment. The porosity values do not vary much, as the average porosity for the sandstone facies is about 15%, for the siltstones it ranges about 7%. The permeability is variable throughout the formation, the values range from 50 to 300 md. Although sandstone has a good porosity and permeability, the siltstone facies exhibit poor petrophysical characteristics. In terms of reservoir characterization, the mineralogical mature, moderately well sorted top most sandstone facies, with appreciable porosity and permeability can be considered as a potential reservoir rock. This study has provided a base for future quantitative studies in this important formation in the area.

Structural evolution of the J-fold; a multi-scalar approach to modeling kinematic fold evolution in the Cordilleran fold-thrust belt, southwestern Montana

NASA Astrophysics Data System (ADS)

Wallace, James W.

The Highway 2 structural complex (HW2SC) is part of the North American western Cordilleran fold-and-thrust belt that extends from northern Wyoming into northwestern Canada. More precisely, the HW2SC is located on the southeastern margin of the Helena salient in what is known as the southwest Montana transverse zone. Based on the location of the HW2SC it appears to have formed as footwall deformation associated with displacement along the southwestern Montana transverse zone. The most prominent structural feature in the HW2SC is the Late-Cretaceous "J-fold", a east-west trending, muliti-hinged, northeast plunging anticline with an associated northeast plunging syncline. The purpose of this study is to provide insight into whether the geometries of thrust-related folds correlate to particular mechanical responses taking place within the folded sedimentary sequences. This is accomplished by conducting a multifaceted examination of the J-fold using high-resolution terrestrial laser scanning combined with detailed field measurements of kinematic indicators, and petrographic analysis of microstructures in thin section. Based on the findings of this study four specific conclusions about the kinematic and mechanical evolution of the J-fold can be made: 1) the J-fold kinematically behaves as a fault-bend fold throughout its structural evolution; 2) the J-fold enjoyed two stages of fault-bend folding deformation that produced its present day geometry; 3) the J-fold has been tectonically thinned by >50% in the Permian Phosphoria and Jurassic Ellis-Rierdon formations located in the Overturned forelimb; and finally 4) the J-fold is mechanically accommodating the thinning in the Overturned forelimb by pressure solution and dissolution of chert grains in the Permian Phosphoria formation and by faulting and shearing in the Jurassic Ellis-Rierdon formation.

Identification and cause of decay of building materials used in the architectural heritage of Bizerte city (Tunisia)

NASA Astrophysics Data System (ADS)

Zoghlami, Karima; Lopez-Arce, Paula; Navarro, Antonia; Zornoza-Indart, Ainara; Gómez, David

2017-04-01

Monuments and historical buildings of Bizerte show a disturbing state of degradation. In order to propose a compatible materials for the restauration works such as stone of substitution and restauration mortars, a geological context was analysed with the objectif to localize historical quarries accompanied by a sedimentological study to identify the exploited geological formations. Petrophysical and chemical caracterisation of both stone and mortars have been carried out. With the aim to determine the origin of the erosion and the degree of stone decay, a combination of micro-destructive and non-destructive techniques have been used on-site and in-lab. Moisture measurements, ultrasonic velocity propagation and water absorption by Karsten pipe test together with polarized light and fluorescence optical microscopy, mercury intrusion porosimetry and ion chromatography analyses were carried out to perform petrophysical characterization of stone samples and determination of soluble salts. For the characterization of mortars, granulometric study was performed to determine the nature of components and their grain size distribution. Thin sections of mortar samples were examined for the petrographical and mineralogical characterization. X-ray diffraction (XRD) analysis of finely pulverized samples was performed in order to identify the mineral crystalline phases of the mortars. Thermal analyses [thermogravimetry (TG)] were performed in order to determine the nature of the binder and its properties. Porosity was determined following UNE-EN 1936 (2007) standart test. Geological and petrographical study showed that historical buildings are essentially built with high porous bioclastic calcarenite partially cemented by calcite which is Würm in age and outcrops all along the northern coast of Bizerte where several historical quarries were identified. Occasionally, two other types of lithologies were used as building stones and they correspond to two varieties of oligocene sandstones (brown quartz-arenite cemented by iron oxide and ochre-green colored sandstone cemented by calcite) and an eocene white limestone corresponding to a fine-grained globigerine wackstone according to Dunham classification. Results of the petrophysical study show that small variations in the petrographic characteristics of the building geomaterials, such as type and degree of cementation, porous network configuration and presence or absence of soluble salts leads to differential stone weathering. Results of study's mortars show that original and restoration mortars have similar mineralogical composition but different grain size distribution and proportion of binder/agregats. They differ equally by the nature of raw materials as demonstrated by the thermal analyses. The study show that little variation of these parameters can affect the durability and the performance of mortars and can accelerate the degradation process of the building stones, especially the oligocene and eocene lithotypes.

Statistical analyses on sandstones: Systematic approach for predicting petrographical and petrophysical properties

NASA Astrophysics Data System (ADS)

Stück, H. L.; Siegesmund, S.

2012-04-01

Sandstones are a popular natural stone due to their wide occurrence and availability. The different applications for these stones have led to an increase in demand. From the viewpoint of conservation and the natural stone industry, an understanding of the material behaviour of this construction material is very important. Sandstones are a highly heterogeneous material. Based on statistical analyses with a sufficiently large dataset, a systematic approach to predicting the material behaviour should be possible. Since the literature already contains a large volume of data concerning the petrographical and petrophysical properties of sandstones, a large dataset could be compiled for the statistical analyses. The aim of this study is to develop constraints on the material behaviour and especially on the weathering behaviour of sandstones. Approximately 300 samples from historical and presently mined natural sandstones in Germany and ones described worldwide were included in the statistical approach. The mineralogical composition and fabric characteristics were determined from detailed thin section analyses and descriptions in the literature. Particular attention was paid to evaluating the compositional and textural maturity, grain contact respectively contact thickness, type of cement, degree of alteration and the intergranular volume. Statistical methods were used to test for normal distributions and calculating the linear regression of the basic petrophysical properties of density, porosity, water uptake as well as the strength. The sandstones were classified into three different pore size distributions and evaluated with the other petrophysical properties. Weathering behavior like hygric swelling and salt loading tests were also included. To identify similarities between individual sandstones or to define groups of specific sandstone types, principle component analysis, cluster analysis and factor analysis were applied. Our results show that composition and porosity evolution during diagenesis is a very important control on the petrophysical properties of a building stone. The relationship between intergranular volume, cementation and grain contact, can also provide valuable information to predict the strength properties. Since the samples investigated mainly originate from the Triassic German epicontinental basin, arkoses and feldspar-arenites are underrepresented. In general, the sandstones can be grouped as follows: i) quartzites, highly mature with a primary porosity of about 40%, ii) quartzites, highly mature, showing a primary porosity of 40% but with early clay infiltration, iii) sublitharenites-lithic arenites exhibiting a lower primary porosity, higher cementation with quartz and Fe-oxides ferritic and iv) sublitharenites-lithic arenites with a higher content of pseudomatrix. However, in the last two groups the feldspar and lithoclasts can also show considerable alteration. All sandstone groups differ with respect to the pore space and strength data, as well as water uptake properties, which were obtained by linear regression analysis. Similar petrophysical properties are discernible for each type when using principle component analysis. Furthermore, strength as well as the porosity of sandstones shows distinct differences considering their stratigraphic ages and the compositions. The relationship between porosity, strength as well as salt resistance could also be verified. Hygric swelling shows an interrelation to pore size type, porosity and strength but also to the degree of alteration (e.g. lithoclasts, pseudomatrix). To summarize, the different regression analyses and the calculated confidence regions provide a significant tool to classify the petrographical and petrophysical parameters of sandstones. Based on this, the durability and the weathering behavior of the sandstone groups can be constrained. Keywords: sandstones, petrographical & petrophysical properties, predictive approach, statistical investigation

Groundwater dolocretes from the Upper Triassic of the Paris Basin, France: a case study of an arid, continental diagenetic facies

USGS Publications Warehouse

Spotl, S.; Wright, V.P.

1992-01-01

The majority of the dolomite consists of a finely crystalline groundmass of dolomicrospar and, less commonly, dolomicrite. Glaebules, irregular spar-filled cracks, spheroidal dolomite, silificiation and vuggy porosity are locally abundant in the massive dolomite. In contrast, biologically induced micromorphological features such as rhizocretions and alveolar-septal fabrics were observed in the thin, nodular dolomite beds. Petrographic observations argue in favour of primary (proto)dolomite precipitation, although early diagenetic replacement of calcite by (proto)dolomite cannot be ruled out. Strontium and carbon isotope data of early diagenetic dolocrete cements and oxygen isotope data of early diagenetic silica indicate an entirely non-marine, continental origin for the groundwaters. -from Authors

Transgressive reef sequences of the Devonian Devils Gate Limestone, Red Hill, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shapiro, R.; Dehler, C.; Flynn, J.

The Devils Gate Limestone at Red Hill, Simpson Park Range, Eureka Co., Nevada is composed of several conformable transgressive sequences cropping out in a series of step-like cliffs 1--5 m high. The general sequence is as follows: (1) a 1--4 m thick in situ boundstone dominated by large, period rugosans, domical and stratiform stromatoporids and rare, 1--3 cm diameter oncolites. Most of the boundstone is composed of small, cylindrical fossils. Petrographic observation revealed them to be mostly Amphipora and Cladopora. The upper portions of these units are packstones composed of Amphipora/Cladopora and, to a lesser degree, small favositids, round stromatoporoidsmore » (3--4 cm diameter), and rip-up clasts. (2) These beds grade upward into a thinly laminated and/or cross-bedded unfossiliferous mudstone. (3) Stratigraphically above the mudstone or in contact with the packstone, is a cross-bedded and/or bioturbated wackestone containing fossils no greater than 2 mm. In thin section, the mottled reddish-grey wackestone is pelletal, with rare lenses of small crinoid columnals. Disarticulated brachiopod shells of low diversity are found near the tops of some of these layers. Community dominance in the reefal units alternates between Amphipora/Cladopora, colonial rugose, and stromatoporoids. Oncolite mounds are common in the uppermost unit. The typical reef succession consists of domical and digitate stromatoporoids growing on the upper surfaces of in place or disturbed, large rugosans, though the reverse has been noted. Tabulate corals encrusted by stromatoporoids are often found in the packstone. It is important to note that often these successions' can be attributed to juxtaposition along styolites.« less

Subgrain boundary analyses in deformed orthopyroxene by TEM/STEM with EBSD-FIB sample preparation technique

NASA Astrophysics Data System (ADS)

Kogure, Toshihiro; Raimbourg, Hugues; Kumamoto, Akihito; Fujii, Eiko; Ikuhara, Yuichi

2014-12-01

High-resolution structure analyses using electron beam techniques have been performed for the investigation of subgrain boundaries (SGBs) in deformed orthopyroxene (Opx) in mylonite from Hidaka Metamorphic Belt, Hokkaido, Japan, to understand ductile deformation mechanism of silicate minerals in shear zones. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) analysis of Opx porphyroclasts in the mylonitic rock indicated that the crystal orientation inside the Opx crystals gradually changes by rotation about the b-axis by SGBs and crystal folding. In order to observe the SGBs along the b-axis by transmission electron microscopy (TEM) or scanning TEM (STEM), the following sample preparation protocol was adopted. First, petrographic thin sections were slightly etched with hydrofluoric acid to identify SGBs in SEM. The Opx crystals whose b-axes were oriented close to the normal of the surface were identified by EBSD, and the areas containing SGBs were picked and thinned for (S) TEM analysis with a focused ion beam instrument with micro-sampling system. High-resolution TEM imaging of the SGBs in Opx revealed various boundary structures from a periodic array of dissociated (100) [001] edge dislocations to partially or completely incoherent crystals, depending on the misorientation angle. Atomic-resolution STEM imaging clearly confirmed the formation of clinopyroxene (Cpx) structure between the dissociated partial dislocations. Moreover, X-ray microanalysis in STEM revealed that the Cpx contains a considerable amount of calcium replacing iron. Such chemical inhomogeneity may limit glide motion of the dislocation and eventually the plastic deformation of the Opx porphyroclasts at a low temperature. Chemical profiles across the high-angle incoherent SGB also showed an enrichment of the latter in calcium at the boundary, suggesting that SGBs are an efficient diffusion pathway of calcium out of host Opx grain during cooling.

Emplacement of pyroclastic density currents (PDCs) in a deep-sea environment: The Val d'Aveto Formation case (Northern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Di Capua, Andrea; Groppelli, Gianluca

2016-12-01

The occurrence of PDC deposits in a foredeep basin sequence, named Val d'Aveto Formation (32-29 Ma, Northern Apennines, Italy), provides new information on the behavior of pyroclastic density currents entering the water. In this work, stratigraphic, petrographic and mineralogical features that characterize three pyroclastic deposits have been described and analyzed in the field (facies and lithological analysis on the blocky-size fraction) and in the laboratory (image analyses on the blocky-size detritus, optical analyses of the microtextures, mineralogical analyses through X-ray powder diffraction (XRPD) and scanning electron microscope with energy dispersive X-ray spectometry (SEM-EDS). The deposits are lapilli- to blocky-size, with a blocky-size fraction constituted of accidental detritus. In thin sections, their groundmass texture varies from porphyritic to eutaxitic where coarser particles become close each others. Growth rims have been also detected around plagioclase crystals. Pyrite habits and oxidation, and plagioclase albitization are consistent with hydrothermal temperature conditions of 200 °C. All these results have been compared with the information provided by modern examples of PDC deposits and laboratory experiments on the behavior of water/hot particles mixing. Grain-to-grain collision has been considered as the main flow mechanism that sustained and avoided the disaggregation of the PDCs entering the water.

Fine-scale structure and micromorphology of the Cricket Flat paleosol, Elgin, Oregon, USA

NASA Astrophysics Data System (ADS)

Murray, K.; Bader, N.

2013-12-01

The Cricket Flat paleosol is located about 9 km east of Elgin, Oregon on Oregon Route 82. The paleosol underlies an olivine basalt of the Powder River Volcanic Field, a sequence of Middle Miocene to Pliocene lavas that overlie the Columbia River Basalt Group in northeastern Oregon. The parent material of the paleosol is a felsic to intermediate lahar that contains leaf and twig fossils as well as tree casts. While some researchers have measured the bulk chemistry and clay mineralogy of this paleosol, no study of its micromorphology has been attempted. In this study we viewed polished thin sections with a petrographic microscope to examine both the parent material and the paleosol. Scanning electron microscopy was used to understand the composition of minerals. Soil texture was analyzed using point counts. Skeleton grains inherited from the parent are mainly plagioclase, orthoclase feldspar, quartz, and volcanic glass. Accessory minerals include titanite, epidote, apatite, and zircon. The paleosol has an argillic horizon with vertic features that are not apparent at the field scale. Diatoms, palynomorphs, and root traces are relatively common in the A horizon of the paleosol. Strong sepic plasmic fabrics and redoximorphic features suggest an environment that was at least seasonally waterlogged and subjected to shrink-swell processes.

Deviation of paleomagnetic directions on basaltic lava flows determined by rock magnetic fabrics

NASA Astrophysics Data System (ADS)

Silva, Pedro; Henry, Bernard; Gallet, Yves; Martins, Sofia; Lopes, Ana; Moreira, Mário; Genevey, Agnès; Mata, João; Nunes, João; Neres, Marta; Meriaux, Anne-Sophie; Madeira, José

2016-04-01

Some paleomagnetic works conducted in lava flows retrieve characteristic remanent directions that shows an inclination shallowing relatively to the expected Geocentric Axial Dipole. Contributions of non-dipole components to the resultant Earth magnetic field and/or deficient time covering of the paleosecular variation are the most pointed causes for such shallowing. Another, but often overlooked source of shallowing, is the magnetic anisotropy carried by lava flows. In order to bring more insights about this research topic, four historical basaltic lava flows (corresponding to nine sampled sites) from Azores (Terceira and Pico islands) were studied. Detailed paleomagnetic and magnetic fabric analyses (anisotropy of magnetic susceptibility AMS and of anhysteretic remanence AARM) were complemented by petrographic observations of oriented thin sections. Our study shows that the majority of the analysed sites display a low degree of anisotropy (corrected degrees of anisotropy, Pj, lower than 1.03), sometimes accompanied by exchanges between principal axes of the magnetic susceptibility ellipsoid. For such cases the corresponding paleomagnetic directions are well grouped with a Fisher distribution. The sites, where Pj is higher than 1.03 (reaching 1.15), present a triaxial magnetic susceptibility ellipsoid and the paleomagnetic directions show a lengthened distribution. Spatial distribution of AMS and AARM ellipsoids axes are very similar. Petrographic observations show flow structures that agree with AMS and AARM ellipsoid. Comparing AMS and main paleomagnetic directions retrieved for lava flows with the highest anisotropy, 20° variation in inclination of paleomagnetic directions is observed. This inclination varies almost linearly with the degree of anisotropy through an inverse correlation. A shift of paleomagnetic declinations is also observed, which agrees with changes in the direction of the maximum principal axes of AMS ellipsoid. These results clearly show that paleomagnetic directions on basaltic rocks can be strongly deviated from the field direction. Accordingly, preliminary analyses of rock fabrics (magnetic and microstructural) are fundamental for such kind of paleomagnetic works. The author wish to acknowledge REGENA project (PTDC/GEO-FIQ/3648/2012) for its major contribution without which this work wouldn't be possible. Publication supported by project FCT UID/GEO/50019/2013 - Instituto Dom Luiz.

Petrographic Descriptions of Selected Rock Specimens From the Meade Peak Phosphatic Shale Member, Phosphoria Formation (Permian), Southeastern Idaho

USGS Publications Warehouse

Johnson, Edward A.; Grauch, Richard I.; Herring, James R.

2007-01-01

Based on petrographic observations of 135 thin sections, rocks in the Meade Peak Phosphatic Shale Member of the Permian Phosphoria Formation in southeastern Idaho can be placed into one of four major lithofacies: organic claystone, muddy siltstone, peloidal phosphorite, and dolomitized calclithite-in order of decreasing abundance. Organic claystones are the most common lithofacies in the Meade Peak. Many of these rocks contain sufficient amounts of silt to make silty, organic claystones a common subtype. Organic claystones commonly contain crystals of muscovite and bioclasts as accessory components, and they are typically parallel laminated. Muddy siltstones are composed primarily of quartz silt, but some feldspar and rare carbonate silt are also present; some rocks are parallel laminated. Phosphate peloids are composed of varying amounts of opaque, complex, and translucent material, and observed internal structures are classified as simple, banded, cored, zoned, oolitic, nucleated, and polynucleated. Opaque, complex, and translucent peloids form the framework grains of three peloidal phosphorite rocks: wackestone phosphorite, packstone phosphorite, and grainstone phosphorite. Wackestone phosphorite is phosphatic-mud supported and contains more than 10 percent peloids; it is the most common type of phosphorite. Packstone phosphorite is peloid supported and contains interstitial phosphatic mud; it is also a common type. Grainstone phosphorite is peloid supported but lacks phosphatic mud; it is the least common type. Dolomitized calclithites contain three types of carbonate grains: macrocrystalline, microcrystalline, and crystalline with a microcrystalline nuclei-in order of decreasing abundance. Based on chemical staining and X-ray diffraction analyses, most of the carbonate is dolomite. Sufficient amounts of quartz silt or muddy material allow some rocks to be called silty dolomitized calclithite or muddy dolomitized calclithite, respectively. Sedimentary structures are absent except in some muddy dolomitized calclithites. Organic claystones, muddy siltstones, and dolomitized calclithites are detrital deposits. Many rocks in the Meade Peak contain calcite and apatite as fracture fillings and vug linings. As expected, peloidal phosphorites are most common in ore zones, and detrital rocks are most common in waste zones. Mine-specific marker beds are mostly composed of dolomitized calclithite.

Publications - GMC 317 | Alaska Division of Geological & Geophysical

Science.gov Websites

DGGS GMC 317 Publication Details Title: Brief petrographic and permeability/porosity analysis of the , Brief petrographic and permeability/porosity analysis of the Kuparuk C Unit core (8741') from the Texaco

Raman Spectroscopy for Mineral Identification and Quantification for in situ Planetary Surface Analysis: A Point Count Method

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Wang, Alian; Rockow, Kaylynn M.; Jolliff, Bradley L.; Korotev, Randy L.; Viskupic, Karen M.

1997-01-01

Quantification of mineral proportions in rocks and soils by Raman spectroscopy on a planetary surface is best done by taking many narrow-beam spectra from different locations on the rock or soil, with each spectrum yielding peaks from only one or two minerals. The proportion of each mineral in the rock or soil can then be determined from the fraction of the spectra that contain its peaks, in analogy with the standard petrographic technique of point counting. The method can also be used for nondestructive laboratory characterization of rock samples. Although Raman peaks for different minerals seldom overlap each other, it is impractical to obtain proportions of constituent minerals by Raman spectroscopy through analysis of peak intensities in a spectrum obtained by broad-beam sensing of a representative area of the target material. That is because the Raman signal strength produced by a mineral in a rock or soil is not related in a simple way through the Raman scattering cross section of that mineral to its proportion in the rock, and the signal-to-noise ratio of a Raman spectrum is poor when a sample is stimulated by a low-power laser beam of broad diameter. Results obtained by the Raman point-count method are demonstrated for a lunar thin section (14161,7062) and a rock fragment (15273,7039). Major minerals (plagioclase and pyroxene), minor minerals (cristobalite and K-feldspar), and accessory minerals (whitlockite, apatite, and baddeleyite) were easily identified. Identification of the rock types, KREEP basalt or melt rock, from the 100-location spectra was straightforward.

The Itataia phosphate-uranium deposit (Ceará, Brazil) new petrographic, geochemistry and isotope studies

NASA Astrophysics Data System (ADS)

Veríssimo, César Ulisses Vieira; Santos, Roberto Ventura; Parente, Clóvis Vaz; Oliveira, Claudinei Gouveia de; Cavalcanti, José Adilson Dias; Nogueira Neto, José de Araújo

2016-10-01

The Itataia phosphate-uranium deposit is located in Santa Quitéria, in central Ceará State, northeastern Brazil. Mineralization has occurred in different stages and involves quartz leaching (episyenitization), brecciation and microcrystalline phase formation of concretionary apatite. The last constitutes the main mineral of Itatiaia uranium ore, namely collophane. Collophanite ore occurs in massive bodies, lenses, breccia zones, veins or episyenite in marble layers, calc-silicate rocks and gneisses of the Itataia Group. There are two accepted theories on the origin of the earliest mineralization phase of Itataia ore: syngenetic (primary) - where the ore is derived from a continental source and then deposited in marine and coastal environments; and epigenetic (secondary) - whereby the fluids are of magmatic, metamorphic and meteoric origin. The characterization of pre- or post-deformational mineralization is controversial, since the features of the ore are interpreted as deformation. This investigation conducted isotopic studies and chemical analyses of minerals in marbles and calc-silicate rocks of the Alcantil and Barrigas Formations (Itataia Group), as well as petrographic and structural studies. Analysis of the thin sections shows at least three phosphate mineral phases associated with uranium mineralizaton: (1) A prismatic fluorapatite phase associated with chess-board albite, arfvedsonite and ferro-eckermannite; (2) a second fluorapatite phase with fibrous radial or colloform habits that replaces calcium carbonate in marble, especially along fractures, with minerals such as quartz, chlorite and zeolite also identified in calc-silicate rocks; and (3) an younger phosphate phase of botryoidal apatite (fluorapatite and hydroxyapatite) related with clay minerals and probably others calcium and aluminum phosphates. Detailed isotopic analysis carried out perpendicularly to the mineralized levels and veins in the marble revealed significant variation in isotopic ratios. Mineralized zones exhibit a decrease in δ13C and δ18O isotope values and a higher 87Sr/86Sr ratio toward the center of the vein. In conjunction with petrographic studies, these changes contesting the hypothesis of a sedimentary origin for uranium and suggest a radiogenic Sr input by alkaline to peralkaline fluids from fertile granites of the end of Brasiliano/Pan-African orogeny, located outside the deposit. The origin of the phosphorous is associated with phosphorite deposits in the same depositional environment of the neoproterozoic supracrustal quartz-pelite-carbonate sediments of the Itataia Group. Considering the studies conducted here and available geological data, three main mineralizing events can be identified in Itataia: (1) an initial high temperature event connected with a sodium metasomatism-related uranium episode, taking place in Borborema Province and its African counterpart; (2) a second lower temperature stage, consisting of a multiphase cataclastic/hydrothermal event limited to fault and paleokarst zones; and (3) a third and final event, developed in frankly oxidizing conditions. The last two involving mixing of hydrothermal and meteoric fluids.

Selecting candidate structures for lithium treatment : what to provide the petrographer along with concrete specimens : tech brief.

DOT National Transportation Integrated Search

2006-02-01

The process of selecting candidate structures (and : appropriate components of structures) for lithium treatment : invariably involves sampling one or several components : of the structures for laboratory investigations, particularly : petrographic e...

Sub-micron Raman Mapping of Ultramafic Fault Rock Textures

NASA Astrophysics Data System (ADS)

Tarling, M. S.; Rooney, J. S.; Smith, S. A. F.; Gordon, K. C.

2016-12-01

Deciphering the often complex temporal and microstructural relationships between the serpentine group minerals - antigorite, chrysotile, lizardite and polygonal serpentine - is essential for a proper understanding of the serpentinization process in a range of geodynamic settings. Conventional techniques such as optical microscopy, quantitative XRD and SEM-EDS often fail to correctly identify the four varieties of serpentine. Transmission electron microscopy can be used to successfully identify these minerals, but complex sample preparation and very small sample sizes (1-10's microns) means that microstructural context is difficult to maintain. Building on previous work (Petriglieri et al. 2015, J. Raman Spectrosc.) that introduced a methodology for Raman mapping on thin sections, we present the initial results of large-area and high-resolution (at the optical limit) Raman mapping that allows us to unambiguously distinguish and contextualise the serpentine minerals within their microstructural context. Measurements were performed on flat, SYTON-polished petrographic thin sections using a Witec Raman microscope equipped with a piezoelectric nano-positioning x-y stage. With a laser wavelength of 532 nm and a 100x dry objective, spatial resolution approaching 360 nm, as predicted by the Abbe equation, can readily be achieved. Minerals are primarily discerned by examining the Raman peaks in the high wavenumber spectral range of 3600-3710 cm-1, corresponding to OH-stretching vibrations. To illustrate the technique, Raman maps were acquired on several samples from the Livingstone Fault, a major terrane boundary in New Zealand that is localized in a mélange of ultramafic rocks including harzburgite and serpentinite. The maps highlight fine-scale intergrowths of antigorite, lizardite, chrysotile and related minerals (e.g. brucite, magnetite) at a sub-micron level over large areas (10's of microns to mm scale), features that are inaccessible or not visible using other techniques. In addition, the high-resolution mapping of discrete magnetite-bearing serpentinite slip surfaces has revealed the presence of 10-50 μm patches of nano-crystalline forsterite and enstatite, which may be the result of localized, faulting-induced, serpentinite dehydration.

Petrology and palynology of the No. 5 block coal bed, northeastern Kentucky

USGS Publications Warehouse

Hower, J.C.; Eble, C.F.; Rathbone, R.F.

1994-01-01

The upper Middle Pennsylvanian (middle Westphalian D equivalent) No. 5 Block coal bed (Eastern Kentucky Coal Field of the Central Appalachian Basin) is a low-sulfur, compliance coal resource, dominantly comprised of dull, inertinite-rich lithotypes. Ash yields tend to be highly variable in the No. 5 Block, as does bed thickness and frequency of bed splitting. This study describes the petrographic, palynologic and geochemical characteristics of the No. 5 Block coal bed, and reports on some temporal and spatial trends among these parameters in eastern-northeastern Kentucky. Petrographically the No. 5 Block coal is predominated by dull, often high-ash lithotypes, with inertinite contents commonly exceeding 30% (mmf). The coal thins to the north-northwest where it tends to be higher in vitrinite and sulfur content. Representatives of large and small lycopsids and ferns (both tree-like and small varieties) dominate the No. 5 Block coal bed palynoflora. Calamite spores and cordaite pollen also occur but are less abundant. Small lycopsid (Densosporites spp. and related crassicingulate genera) and tree fern (e.g. Punctatisporites minutus, Laevigatosporites globosus) spore taxa are most abundant in dull lithotypes. Bright lithotypes contain higher percentages of arboreous lycopsid spores (Lycospora spp.). Regionally, the No. 5 Block coal contains abundant Torispora securis, a tree fern spore specially adapted for desiccation prevention. This, along with overall high percentages of inertinite macerals, suggest that peat accumulation may have taken place in a seasonally dry (?) paleoclimate. The No. 5 Block coal bed thickens rather dramatically in a NW-SE direction, as does the frequency of coal bed splitting. This phenomenon appears to be related to increased accomodation space in the southeastern portion of the study area, perhaps via penecontemporaneous growth faulting. Maceral and palynomorph variations within the bed correspond with these changes. Thin coal along the northwestern margin tends to be vetrinite rich and contains abundant Lycospora, perhaps reflecting relatively stable peat-forming conditions. Thicker coal to the southeast contains more inertinite, high-ash coal layers, and inorganic partings. Spore floras contain more small lycopsid and tree fern components and are temporally variable, perhaps indicating a more unstable peat-forming environment. ?? 1994.

Hydrogeochemical and isotopic studies of groundwater in the middle voltaian aquifers of the Gushegu district of the Northern region

NASA Astrophysics Data System (ADS)

Salifu, Musah; Yidana, Sandow Mark; Anim-Gyampo, Maxwell; Appenteng, Michael; Saka, David; Aidoo, Felix; Gampson, Enoch; Sarfo, Mark

2017-06-01

This work is to establish the hydrochemistry and origin of groundwater in some parts of the Gushegu district of the Northern Region of Ghana. Hydrochemical data from 19 groundwater and 7 rock samples have been used to evaluate water quality, water types, and sources of various ions as well as origin of the groundwater. The study results show that the quality of groundwater from the area is generally not good due to their fluoride (F-), bicarbonate (HCO3 -) and electrical conductivity (EC) concentrations. The F- contents of the groundwater have values as high as 1.97 mg/L, with 53 % of the groundwater having concentrations of F- exceeding the WHO recommended allowable limits. These high F- values have the potential of causing serious health problems such as kidney failure, dental and skeletal fluorosis, reproductive problem and reduction in intelligent quotient of consumers. A plot of Gibbs diagram reveals that rock weathering and precipitation are the major hydrogeochemical processes regulating the water chemistry of the study area. Petrographic thin-section analyses of rock samples identify minerals present to be muscovite, plagioclase feldspars, quartz, sericite and iron oxide. Stable isotope (18O and 2H) composition of the waters reveals that most of the groundwater is likely to be recharged from local precipitation, indicating their meteoric origin. Some samples, however, showed considerable evaporation.

The Petrographic Distinction between Basalt and Andesite Based upon the Arrested Fractionation of Plagioclase Phenocrysts.

ERIC Educational Resources Information Center

Garlick, G. Donald; Garlick, Benjamin J.

1987-01-01

Discusses the need to take into account the effects of arrested fractional crystallization in the petrographic classification of volcanic rocks containing plagioclase phenocrysts. Describes the development and use of a computer program to accomplish this task graphically. (TW)

A modification of procedures for petrographic analysis of tertiary Indonesian coals

NASA Astrophysics Data System (ADS)

Moore, T. A.; Ferm, J. C.

A study undertaken to characterize the Eocene coals from southeast Kalimantan has shown that standard preparation procedures fail to capture some basic petrographic properties of the coal. Modification of these procedures permits recognition of distinct plant parts and tissues embedded in finer grained matrix components. Plant parts and tissues can be classified on the basis of morphology and degree of degradation. The highest concentration and best preservation of plant parts and tissues occurs in banded coal and is lowest in the non-banded coal. Use of these procedures, which relates megascopic appearance to petrographic character, should allow more precise utilization of the coal.

Geochemical and petrographic studies of melt-rich breccias from the Chicxulub crater

NASA Astrophysics Data System (ADS)

Vera-Sanchez, P.; Urrutia-Fucugauchi, J.; Morton-Bermea, O.; Soler-Arechalde, A.; Reyes-Salas, M.; Lozano-Santamaria, R.; Linares-Lopez, C.; Rebolledo-Vieyra, M.

2003-04-01

The proposal by Alvarez et al. (1980) for an extraterrestrial bolide impact marking the Cretaceous/Tertiary boundary was based on the anomalous Ir content in Italian and Danish K/T clay layers. The clay layer with a worldwide distribution and enriched in platinum group elements, shocked quartz and other impact-generated features has come to be interpreted as the global ejecta layer produced by a large impact that formed the Chicxulub crater. The ~200 km diameter crater is located in the carbonate platform of northwestern Yucatan peninsula, Mexico. The crater is covered by a thick sequence of Tertiary sediments, with no surface exposures. The National University of Mexico conducted a drilling program with continuous core recovery, in which three boreholes (UNAM wells 5, 6 and 7) sampled the impact breccia sequences. Deeper drilling inside the carter has been carried out as part of the ICDP program with drilling of the Yaxcopoil-1 borehole, which also cored a section of the impact breccias. The Yaxcopoil-1 borehole has been completed as part of the Chicxulub Scientific Drilling Project. In this work, we report on the geochemical and petrographic studies of selected samples from the impact breccia sequence recovered in the Yaxcopoil-1 borehole inside the Chicxulub crater. One of the major questions emerging after the interpretation of Chicxulub as the K/T boundary impact site and its link to the global ejecta layer has been the nature of the impacting body. Studies have addressed this question from distinct fields, including investigation of the ejecta deposits near and far from the crater, from the crater itself, from impact records on the Moon and other bodies, searching for surviving fragments in K/T boundary sections, etc. The search for material with a possible small component associated to the impactor could open unique research opportunities to further understand the impact event. The melt breccia samples examined exhibit different textures and chemical composition, suggesting a complex composition. Rare earth element plots for the various fragments are on the other hand similar. We report the initial results of the petrographic, microprobe, ICP-MS, X-ray fluorescence and X-ray diffraction studies.

QEMSCAN+LAICPMS: a new tool for petrochronology and sedimentary provenance analysis

NASA Astrophysics Data System (ADS)

Vermeesch, Pieter; Rittner, Martin; Omma, Jenny

2017-04-01

Only a relatively small number of rock-forming minerals contain sufficiently high concentrations of naturally occurring radioactive parent isotopes and sufficiently low background concentrations of the corresponding daughter isotopes to be suitable for geochronology. The first step in most geochronological studies is to extract these datable minerals from the host rock using a combination of magnetic and density separation techniques, a process that is tedious and time consuming. We here present a new method to avoid mineral separation by coupling a QEMSCAN electron microscope to an LA-ICP-MS instrument. Given a polished hand specimen, a petrographic thin section, or a grain mount, the QEMSCAN+LAICPMS method produces chemical and mineralogical maps from which the X-Y coordinates of the datable mineral are extracted. These coordinates are subsequently passed on to the laser ablation system for isotopic and, hence, geochronological analysis. QEMSCAN+LAICPMS can be applied to a wide range of problems in igneous, metamorphic and sedimentary geology, as is illustrated with three case studies. In the first case study, a 3 × 4 cm slab of polished granite from the L'Erée pluton in Guernsey is scanned for zircon. This yields 23 U-Pb ages resulting in a concordia age of 615 ± 2 Ma. The second case study re-investigates a paragneiss from an ultra-high pressure terrane in the Qaidam Basin (Qinghai, China) that was previously analysed by conventional petrography, electron microscopy and SIMS zircon U-Pb analysis. In this example, the QEMSCAN revealed 107 small (20 μm) metamorphic zircons that were analysed by LA-ICP-MS to constrain the 430 Ma age of peak metamorphism. The third and final case study investigates the mineralogy and geochronology of sedimentary rocks of the Ordovician Sarah Formation (Saudi Arabia). We analysed 44 outcrop samples and a further 35 subsurface samples, resulting in a dataset comprising 10,000 detrital zircon U-Pb ages and 79 heavy mineral compositions and petrographic analyses. Jointly considering this enormous dataset by 3-way multidimensional scaling paints a remarkably simple picture of sandstone compositions that are determined by a combination of provenance and diagenesis. In conclusion, the QEMSCAN+LAICPMS method represents an efficient and cost effective way to obtain chemical and isotopic compositions on the same sample, which improves both the quantity and quality of geological data.

Diagenesis of the Oligocene-Miocene rocks of the Upper Floridan and Intermediate aquifer systems by meteoric and mixing-zone waters in southwest Florida

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weedman, S.D.; McCartan, L.

1993-03-01

Optical and SEM of samples from 6 cores of Oligocene and Miocene rocks that compose portions of the Florida and Intermediate aquifers and the intervening semiconfining unit documents meteoric and mixing-zone (seawater and fresh carbonate ground water) diagenesis inferred to have occurred over several cycles of sea level change. Dolomite, limestone, sandstone, and claystone of the Suwannee Formation and the Arcadia Formation (Hawthorn Group) were examined. Core samples from time-equivalent strata in two E--W transects in Manatee, Hardee, Highlands, Sarasota, and DeSoto Counties are estimated to be 16--33 Ma on the basis of [sup 87]Sr/[sup 86]Sr ratios from unaltered molluskmore » shells and by molluscan biostratigraphy. Lithostratigraphic correlations are based on examination of 19 cores, 62 thin sections, 60 geophysical logs, and mineralogy determined by X-ray diffraction. Diagenetic indicators that the authors tracked petrographically include shell micritization, shell dissolution, equant and (or) fibrous CaCO[sub 3] cement, neomorphism, dolomite, etched phosphate grains, echinoderm fragment syntaxial overgrowths, and amorphous silica pore lining. Infiltration of meteoric water caused dissolution of carbonate minerals, especially aragonite, and precipitation of equant calcite crystals in voids of dissolved fossils and in pore spaces between grains. The silica was precipitated as pore linings in zones having soil textures. Observed replacement of calcite by limpid dolomite is consistent with modeling predictions of mixing-zone diagenesis. Etched crystals of limpid dolomite may indicate freshwater dissolution of a mixing-zone precipitate. Mapping of regional unconformities revealed pronounced thickening and thinning of some units. Evidence of meteoric water diagenesis is observed in the upper 600 ft of the transects examined. Evidence of mixing-zone diagenesis is observed at varying depths, but appears to increase in abundance and thickness toward the west.« less

Early Archean spherule beds of possible impact origin from Barberton, South Africa: A detailed mineralogical and geochemical study

NASA Technical Reports Server (NTRS)

Koeberl, Christian; Reimold, Wolf Uwe; Boer, Rudolf H.

1992-01-01

The Barberton Greenstone belt is a 3.5- to 3.2-Ga-old formation situated in the Swaziland Supergroup near Barberton, northeast Transvaal, South Africa. The belt includes a lower, predominantly volcanic sequence, and an upper sedimentary sequence (e.g., the Fig Tree Group). Within this upper sedimentary sequence, Lowe and Byerly identified a series of different beds of spherules with diameters of around 0.5-2 mm. Lowe and Byerly and Lowe et al. have interpreted these spherules to be condensates of rock vapor produced by large meteorite impacts in the early Archean. We have collected a series of samples from drill cores from the Mt. Morgan and Princeton sections near Barberton, as well as samples taken from underground exposures in the Sheba and Agnes mines. These samples seem much better preserved than the surface samples described by Lowe and Byerly and Lowe et al. Over a scale of just under 30 cm, several well-defined spherule beds are visible, interspaced with shales and/or layers of banded iron formation. Some spherules have clearly been deposited on top of a sedimentary unit because the shale layer shows indentions from the overlying spherules. Although fresher than the surface samples (e.g., spherule bed S-2), there is abundant evidence for extensive alteration, presumably by hydrothermal processes. In some sections of the cores sulfide mineralization is common. For our mineralogical and petrographical studies we have prepared detailed thin sections of all core and underground samples (as well as some surface samples from the S-2 layer for comparison). For geochemical work, layers with thicknesses in the order of 1-5 mm were separated from selected core and underground samples. The chemical analyses are being performed using neutron activation analysis in order to obtain data for about 35 trace elements in each sample. Major elements are being determined by XRF and plasma spectrometry. To clarify the history of the sulfide mineralization, sulfur isotopic compositions are being determined.

Publications - GMC 232 | Alaska Division of Geological & Geophysical

Science.gov Websites

Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska DGGS GMC 232 Publication Details Title: Petrographic analysis and formation damage potential of core Reference Hickey, J.J., 1994, Petrographic analysis and formation damage potential of core plugs (12,017

Artifacts in slab average-intensity-projection images reformatted from JPEG 2000 compressed thin-section abdominal CT data sets.

PubMed

Kim, Bohyoung; Lee, Kyoung Ho; Kim, Kil Joong; Mantiuk, Rafal; Kim, Hye-ri; Kim, Young Hoon

2008-06-01

The objective of our study was to assess the effects of compressing source thin-section abdominal CT images on final transverse average-intensity-projection (AIP) images. At reversible, 4:1, 6:1, 8:1, 10:1, and 15:1 Joint Photographic Experts Group (JPEG) 2000 compressions, we compared the artifacts in 20 matching compressed thin sections (0.67 mm), compressed thick sections (5 mm), and AIP images (5 mm) reformatted from the compressed thin sections. The artifacts were quantitatively measured with peak signal-to-noise ratio (PSNR) and a perceptual quality metric (High Dynamic Range Visual Difference Predictor [HDR-VDP]). By comparing the compressed and original images, three radiologists independently graded the artifacts as 0 (none, indistinguishable), 1 (barely perceptible), 2 (subtle), or 3 (significant). Friedman tests and exact tests for paired proportions were used. At irreversible compressions, the artifacts tended to increase in the order of AIP, thick-section, and thin-section images in terms of PSNR (p < 0.0001), HDR-VDP (p < 0.0001), and the readers' grading (p < 0.01 at 6:1 or higher compressions). At 6:1 and 8:1, distinguishable pairs (grades 1-3) tended to increase in the order of AIP, thick-section, and thin-section images. Visually lossless threshold for the compression varied between images but decreased in the order of AIP, thick-section, and thin-section images (p < 0.0001). Compression artifacts in thin sections are significantly attenuated in AIP images. On the premise that thin sections are typically reviewed using an AIP technique, it is justifiable to compress them to a compression level currently accepted for thick sections.

Pieces of Other Worlds - Enhance YSS Education and Public Outreach Events with Extraterrestrial Samples

NASA Astrophysics Data System (ADS)

Allen, C.

2010-12-01

During the Year of the Solar System spacecraft will encounter two comets; orbit the asteroid Vesta, continue to explore Mars with rovers, and launch robotic explorers to the Moon and Mars. We have pieces of all these worlds in our laboratories. Extensive information about these unique materials, as well as actual lunar samples and meteorites, is available for display and education. The Johnson Space Center (JSC) curates NASA's extraterrestrial samples to support research, education, and public outreach. At the current time JSC curates five types of extraterrestrial samples: Moon rocks and soils collected by the Apollo astronauts Meteorites collected on US expeditions to Antarctica (including rocks from the Moon, Mars, and many asteroids including Vesta) “Cosmic dust” (asteroid and comet particles) collected by high-altitude aircraft Solar wind atoms collected by the Genesis spacecraft Comet and interstellar dust particles collected by the Stardust spacecraft These rocks, soils, dust particles, and atoms continue to be studied intensively by scientists around the world. Descriptions of the samples, research results, thousands of photographs, and information on how to request research samples are on the JSC Curation website: http://curator.jsc.nasa.gov/ NASA is eager for scientists and the public to have access to these exciting samples through our various loan procedures. NASA provides a limited number of Moon rock samples for either short-term or long-term displays at museums, planetariums, expositions, and professional events that are open to the public. The JSC Public Affairs Office handles requests for such display samples. Requestors should apply in writing to Mr. Louis Parker, JSC Exhibits Manager. He will advise successful applicants regarding provisions for receipt, display, and return of the samples. All loans will be preceded by a signed loan agreement executed between NASA and the requestor's organization. Email address: louis.a.parker@nasa.gov Sets of twelve thin sections of Apollo lunar samples and sets of twelve thin sections of meteorites are available for short-term loan from JSC Curation. The thin sections are designed for use in college and university courses where petrographic microscopes are available for viewing. Requestors should contact Ms. Mary Luckey, Education Sample Curator. Email address: mary.k.luckey@nasa.gov NASA also loans sets of Moon rocks and meteorites for use in classrooms, libraries, museums and planetariums. Lunar samples (three soils and three rocks) are encapsulated in a six-inch diameter clear plastic disk. Disks containing six different samples of meteorites are also available. A CD with PowerPoint presentations, a classroom activity guide, and additional printed material accompany the disks. Educators may qualify for the use of these disks by attending a security certification workshop sponsored by NASA's Aerospace Education Services Program (AESP). Contact Ms. Margaret Maher, AESP Director. Email address: mjm67@psu.edu Please take advantage of the wealth of data and the samples that we have from an exciting variety of solar system bodies.

Quantification of the effects of secondary matrix on the analysis of sandstone composition, and a petrographic-chemical technique for retrieving original framework grain modes of altered sandstones.

PubMed

Cox, R; Lowe, D R

1996-05-01

Most studies of sandstone provenance involve modal analysis of framework grains using techniques that exclude the fine-grained breakdown products of labile mineral grains and rock fragments, usually termed secondary matrix or pseudomatrix. However, the data presented here demonstrate that, when the proportion of pseudomatrix in a sandstone exceeds 10%, standard petrographic analysis can lead to incorrect provenance interpretation. Petrographic schemes for provenance analysis such as QFL and QFR should not therefore be applied to sandstones containing more than 10% secondary matrix. Pseudomatrix is commonly abundant in sandstones, and this is therefore a problem for provenance analysis. The difficulty can be alleviated by the use of whole-rock chemistry in addition to petrographic analysis. Combination of chemical and point-count data permits the construction of normative compositions that approximate original framework grain compositions. Provenance analysis is also complicated in many cases by fundamental compositional alteration during weathering and transport. Many sandstones, particularly shallow marine deposits, have undergone vigorous reworking, which may destroy unstable mineral grains and rock fragments. In such cases it may not be possible to retrieve provenance information by either petrographic or chemical means. Because of this, pseudomatrix-rich sandstones should be routinely included in chemical-petrological provenance analysis. Because of the many factors, both pre- and post-depositional, that operate to increase the compositional maturity of sandstones, petrologic studies must include a complete inventory of matrix proportions, grain size and sorting parameters, and an assessment of depositional setting.

Shock metamorphism and impact melting in small impact craters on Earth: Evidence from Kamil crater, Egypt

NASA Astrophysics Data System (ADS)

Fazio, Agnese; Folco, Luigi; D'Orazio, Massimo; Frezzotti, Maria Luce; Cordier, Carole

2014-12-01

Kamil is a 45 m diameter impact crater identified in 2008 in southern Egypt. It was generated by the hypervelocity impact of the Gebel Kamil iron meteorite on a sedimentary target, namely layered sandstones with subhorizontal bedding. We have carried out a petrographic study of samples from the crater wall and ejecta deposits collected during our first geophysical campaign (February 2010) in order to investigate shock effects recorded in these rocks. Ejecta samples reveal a wide range of shock features common in quartz-rich target rocks. They have been divided into two categories, as a function of their abundance at thin section scale: (1) pervasive shock features (the most abundant), including fracturing, planar deformation features, and impact melt lapilli and bombs, and (2) localized shock features (the least abundant) including high-pressure phases and localized impact melting in the form of intergranular melt, melt veins, and melt films in shatter cones. In particular, Kamil crater is the smallest impact crater where shatter cones, coesite, stishovite, diamond, and melt veins have been reported. Based on experimental calibrations reported in the literature, pervasive shock features suggest that the maximum shock pressure was between 30 and 60 GPa. Using the planar impact approximation, we calculate a vertical component of the impact velocity of at least 3.5 km s-1. The wide range of shock features and their freshness make Kamil a natural laboratory for studying impact cratering and shock deformation processes in small impact structures.

Reconnaissance survey of the Duolun ring structure in Inner Mongolia: Not an impact structure

NASA Astrophysics Data System (ADS)

Xu, Xiaoming; Kenkmann, Thomas; Xiao, Zhiyong; Sturm, Sebastian; Metzger, Nicolai; Yang, Yu; Weimer, Daniela; Krietsch, Hannes; Zhu, Meng-Hua

2017-09-01

The Duolun basin, which is located in Inner Mongolia, China, has been proposed to be an impact structure with an apparent rim diameter of about 70, or even 170 km. The designation as an impact structure was based on its nearly circular topography, consisting of an annular moat that surrounds an inner hummocky region, and the widespread occurrences of various igneous rocks, polymict breccias, and deformed crustal rocks. Critical shock metamorphic evidence is not available to support the impact hypothesis. We conducted two independent reconnaissance field surveys to this area and studied the lithology both within and outside of the ring structure. We collected samples from all lithologies that might contain evidence of shock metamorphism as suggested by their locations, especially those sharing similar appearances with impact breccias, suevites, impact melt rocks, and shatter cones. Field investigation, together with thin-section examination, discovered that the suspected impact melt rocks are actually Early Cretaceous and Late Jurassic lava flows and pyroclastic deposits of rhyolitic to trachytic compositions, and the interpreted impact glass is typical volcanic glass. Petrographic analyses of all the samples reveal no indications for shock metamorphic overprint. All these lines of evidence suggest that the Duolun basin was not formed through impact cratering. The structural deformation and spatial distribution pattern of the igneous rocks suggest that the Duolun basin is most likely a Jurassic-Cretaceous complex rhyolite caldera system that has been partly filled with sediments forming an annular basin, followed by resurgent doming of the central area.

Diagenetic effects of compaction on reservoir properties: The case of early callovian ``Dalle Nacrée'' formation (Paris basin, France)

NASA Astrophysics Data System (ADS)

Nader, Fadi H.; Champenois, France; Barbier, Mickaël; Adelinet, Mathilde; Rosenberg, Elisabeth; Houel, Pascal; Delmas, Jocelyne; Swennen, Rudy

2016-11-01

The impact of compaction diagenesis on reservoir properties is addressed by means of observations made on five boreholes with different burial histories of the Early Callovian ;Dalle Nacrée; Formation in the Paris Basin. Petrographic analyses were carried out in order to investigate the rock-texture, pore space type and volume, micro-fabrics, and cement phases. Based on the acquired data, a chronologically ordered sequence of diagenetic events (paragenesis) for each borehole was reconstructed taking the burial history into account. Point counting and a segmentation algorithm (Matlab) were used to quantify porosity, as well as the amounts of grain constituents and cement phases on scanned images of studied thin sections. In addition, four key samples were analyzed by 3D imaging using microfocus X-ray computer tomography. Basin margin grainstones display a different burial diagenesis when compared to basin centre grainstones and wackestones. The former have been affected by considerable cementation (especially by blocky calcite) prior to effective burial, in contrast to the basin centre lithologies where burial and compaction prevailed with relatively less cementation. Fracturing and bed-parallel stylolitization, observed especially in basinal wackestone facies also invoke higher levels of mechanical and chemical compaction than observed in basin marginal equivalents. Compaction fluids may have migrated at the time of burial from the basin centre towards its margins, affecting hence the reservoir properties of similar rock textures and facies and resulting in cross-basin spatial diagenetic heterogeneities.

DOSAGE DES ELEMENTS EN TRACE DES CALCAIRES AU SERVICE DE L'ARCHEOLOGIE

DOE Office of Scientific and Technical Information (OSTI.GOV)

BLANC,A.; HOLMES,L.; HARBOTTLE,G.

1998-05-01

Numerous quarries in the Lutetian limestone formations of the Paris Basin provided stone for the building and the decoration of monuments from antiquity to the present. To determine the origin of stone used for masonry and sculptures in these monuments, a team of geologists and archaeologists has investigated 300 quarries and collected 2,300 samples. Petrographic and paleontologic examination of thin sections allows geologists to distinguish Lutetian limestones from Jurassic and Cretaceous limestones. Geologists also seek to formulate hypotheses regarding the origin of Lutetian limestones used for building and sculpture in the Paris region. In the search for the sources ofmore » building and sculptural stone, the analytical methods of geologists are limited because often several quarries produce the same lithofacies. A new tool is now available, however, to attack questions of provenance raised by art historians. Because limestones from different sources have distinctive patterns of trace-element concentrations, compositional analysis by neutron activation allows them to compare building or sculptural stone from one monument with stone from quarries or other monuments. This analytical method subjects a powdered limestone sample to standard neutron activation analysis procedures at Brookhaven National Laboratory. With the help of computer programs, the compositional fingerprints of Lutetian limestones can be determined and stored in a database. The limestone database contains data for approximately 2,100 samples from monuments, sculptures and quarries. It is particularly rich in samples from the Paris Basin.« less

The mineralogy, petrology, and composition of anomalous eucrite Emmaville

NASA Astrophysics Data System (ADS)

Barrett, T. J.; Mittlefehldt, D. W.; Greenwood, R. C.; Charlier, B. L. A.; Hammond, S. J.; Ross, D. K.; Anand, M.; Franchi, I. A.; Abernethy, F. A. J.; Grady, M. M.

2017-04-01

The Emmaville eucrite is a relatively poorly studied basaltic achondrite with an anomalous oxygen isotope signature. In this study, we report comprehensive mineralogical, petrographic, and geochemical data from Emmaville in order to understand its petrogenesis and relationship with the basaltic eucrites. Emmaville is an unusually fine-grained, hornfelsic-textured metabasalt with pervasive impact melt veins and mineral compositions similar to those of typical basaltic eucrites. The major and trace element bulk composition of Emmaville is also typical of a basaltic eucrite. Three separated individual lithologies were also analyzed for O isotopes; a dark gray fraction (E1), a shocked lithology (E2), and a lighter gray portion (E3). Fractions E1 and E2 shared similar O isotope compositions to the bulk sample (E-B), whereas the lighter gray portion (E3) is slightly elevated in Δ17O and significantly elevated in δ18O compared to bulk. No evidence for any exogenous material is observed in the thin sections, coupled with the striking compositional similarity to typical basaltic eucrites, appears to preclude a simple impact-mixing hypothesis. The O-isotopes of Emmaville are similar to those of Bunburra Rockhole, A-881394, and EET 92023, and thus distinct from the majority of the HEDs, despite having similarities in petrology, mineral, and bulk compositions. It would, therefore, seem plausible that all four of these samples are derived from a single HED-like parent body that is isotopically distinct from that of the HEDs (Vesta) but similar in composition.

Diverse microbially induced sedimentary structures from 1 Ga lakes of the Diabaig Formation, Torridon Group, northwest Scotland

NASA Astrophysics Data System (ADS)

Callow, Richard H. T.; Battison, Leila; Brasier, Martin D.

2011-08-01

The siliciclastic lacustrine rocks of the ~ 1000 Ma Diabaig Formation, northwest Scotland, contain a remarkable diversity of macroscopic structures on bedding planes that can be compared with various kinds of microbially induced sedimentary structures (MISS). Field sedimentological investigations, combined with laboratory analysis of bedding planes and petrographic study of thin sections have allowed us to characterise a range of depositional environments and document the spectrum of biological structures. MISS are reported from frequently subaerial environments, through commonly submerged facies, and down to permanently sub-wavebase settings. Palaeoenvironmental conditions (water depth, exposure, hydrodynamic energy) control the distribution of MISS within these facies. This demonstrates that mat-forming microbial communities were arguably well adapted to low light levels or periodic exposure. Some MISS from the Diabaig Formation are typical of Precambrian microbial mats, including reticulate fabrics and 'old elephant skin' textures. In addition to these, a number of new and unusual fabrics of putative microbial origin are described, including linear arrays of ridges and grooves (cf. 'Arumberia') and discoidal structures that are comparable with younger Ediacaran fossils such as Beltanelliformis. These observations indicate that benthic microbial ecosystems were thriving in freshwater lake systems ~ 1000 Ma, and indicate how microbially induced sedimentary structures may be applied as facies indicators for Proterozoic lacustrine environments. The discovery of structures closely resembling Ediacaran fossils (cf. Beltanelliformis) also serves to highlight the difficulty of interpreting simple discoidal bedding plane structures as metazoan fossils.

Spatial and vertical distribution of soil physico-chemical properties and the content of heavy metals in the pedosphere in Poland

Treesearch

Marek Degorski

1998-01-01

The lithological and petrographical characteristics of soil pedogenesis was determined, and the spatial and vertical distribution of some soil physico-chemical properties (including heavy metal content) were studied along two transects in Poland. The genetic horizon for 22 soil profiles were described for particle size and petrographic composition, quartz grain...

Content Model Use and Development to Redeem Thin Section Records

NASA Astrophysics Data System (ADS)

Hills, D. J.

2014-12-01

The National Geothermal Data System (NGDS) is a catalog of documents and datasets that provide information about geothermal resources located primarily within the United States. The goal of NGDS is to make large quantities of geothermal-relevant geoscience data available to the public by creating a national, sustainable, distributed, and interoperable network of data providers. The Geological Survey of Alabama (GSA) has been a data provider in the initial phase of NGDS. One method by which NGDS facilitates interoperability is through the use of content models. Content models provide a schema (structure) for submitted data. Schemas dictate where and how data should be entered. Content models use templates that simplify data formatting to expedite use by data providers. These methodologies implemented by NGDS can extend beyond geothermal data to all geoscience data. The GSA, using the NGDS physical samples content model, has tested and refined a content model for thin sections and thin section photos. Countless thin sections have been taken from oil and gas well cores housed at the GSA, and many of those thin sections have related photomicrographs. Record keeping for these thin sections has been scattered at best, and it is critical to capture their metadata while the content creators are still available. A next step will be to register the GSA's thin sections with SESAR (System for Earth Sample Registration) and assign an IGSN (International Geo Sample Number) to each thin section. Additionally, the thin section records will be linked to the GSA's online record database. When complete, the GSA's thin sections will be more readily discoverable and have greater interoperability. Moving forward, the GSA is implementing use of NGDS-like content models and registration with SESAR and IGSN to improve collection maintenance and management of additional physical samples.

Rheological Implications of Peridotite Serpentinization Reactions and Orogenic Serpentinite Emplacement by "Cold" Intrusion under Hydrothermal Conditions (T < 550°C) in the California Coast Ranges: Insights from Dissolution and Growth Microstructures

NASA Astrophysics Data System (ADS)

Kirby, Stephen

2017-04-01

The natural system represented by a simplified serpentinization and dehydration reaction: olivine + water <-> serpentine + associated minerals has unusual properties from the standpoint of rheology and flow. In the absence of free water, the layer-silicate serpentine at T < 500°C is moderately strong, with a coefficient of friction of 0.6 over the range that it is stable, poor (001) cleavage, conchoidal fracture, high plastic yield strength, consequent to its difficult intracrystalline slip owing to its difficult basal slip that require breaking the Mg-O and Mg-OH bonds in the Mg interlayer and lack of easy slip on non-basal glide planes. The serpentinite-forming reaction involves a large mass uptake of water and volume increase. In excess of the amount of water to complete the reaction, serpentinites in orogens generally show abundant evidence of deformation under hydrothermal conditions, such as vein filling and deformation-induced dissolution and growth processes. Recent petrographic studies of serpentinite block-and-matrix samples collected from the San Francisco Bay Area of California by Uno and Kirby (EPSL Submitted, 2017), Lewis and Kirby (2015 AGU Poster Abstract) verify the importance of this deformation mechanism in those rocks. Finally, dozens of geologic papers published from 1935 to 1999 on these same serpentinite bodies, including those based geologic mapping on surface and underground mercury mine workings, concluded that they are cold intrusions injected as plugs, sills, dikes and fault fillings as enabled by the rheological effects of hydrothermal fluids as described above (Kellner and Kirby, 2016 AGU Poster Abstract). Some of these bodies may have been driven upward as diapirs and/or by volume expansion while being serpentinized during ascent through the crust. Evidence for these reactions has been found in thin sections found in nearly several hundred thin sections cut from block samples from 21 such bodies (Uno and Kirby, 2017; Madeline Lewis and Caroline Kellner, unpublished, 2015-2016). Finally, we discuss a model that gives insight into the possible source of water, the source of the ultramafic rocks, and metamorphic rocks entrained in them (Kirby, Wang, and Brocher, EPS 2014).

Evidence for a composite organic-inorganic fabric of belemnite rostra: implication for palaeoceanography

NASA Astrophysics Data System (ADS)

Hoffmann, Rene; Richter, Detlev K.; Neuser, Rolf D.; Jöns, Niels; Linzmeier, Benjamin J.; Lemanis, Robert E.; Fusseis, Florian; Xiao, Xianghui; Immenhauser, Adrian

2017-04-01

Carbonate skeletons of fossil marine organisms are widely used to reconstruct palaeoenvironments. Specifically, the geochemistry of Jurassic and Cretaceous belemnite rostra is commonly applied to reconstruct palaeoseawater properties. This is due to the assumption that belemnites, as member of the mollusc group, precipitated their rostra in equilibrium with the palaeoenvironment and secondly it was assumed that rostra represent primary dense low Mg calcite structures and relatively stable against diagenetic overprinting. More recently an increasing number of published data, show significant scatter in geochemical data (e.g., d18O, d13C, element/Ca ratio) when comparing belemnite rostra from the same stratigraphic level or within a single belemnite rostrum. This scatter is not explained by differential diagenetic overprint alone but also by vertical and horizontal migration patterns, seasonality, or changes in salinity. In order to test for an ultrastructural-related explanation for the observed scatter we employed a wide range of state-of-the-art analytical tools, e.g., cathodoluminescence, fluorescence- and confocal laser fluorescence microscopy, scanning electron microscopy equipped with a backscatter detector, electron microprobe analysis, electron backscatter diffraction imaging to thin sections and ultra-thin sections of well-preserved specimens. We found petrographic evidence that the primary, i.e. biogenic, ultrastructure of rostra of Megateuthis (Middle Jurassic) and Belemnitella and Gonioteuthis (Late Cretaceous) was not a dense calcite structure, but contained primary porosity. The biogenic ultrastructure consists of a filigree framework of tetrahedrons of variable size with branches forming a honeycomb-like network. Data presented here suggest that these rostra yielded as much as 50 to 90% primary pore space. We propose that the pore space was originally filled with body fluid and/or organic compounds during the life time of these organisms in analogy with modern cephalopods. Intra-rostral porosity was occluded post mortem by earliest diagenetic isopachous calcite cements of a non-biogenic origin. These may have been precipitated due to increased alkalinity related to the decay of organic matter. If this holds true, then the resulting fabric represents a composite biogenic/abiogenic structure precipitated at different times and depths in the water column. We suggest that these findings have significance for those using belemnite rostra as archives of their palaeoenvironment, for the reconstruction of belemnite palaeoecology, and for the functional interpretation of belemnite rostra.

A microfluidic approach to water-rock interactions using thin rock sections: Pb and U sorption onto thin shale and granite sections.

PubMed

Oh, Youn Soo; Jo, Ho Young; Ryu, Ji-Hun; Kim, Geon-Young

2017-02-15

The feasibility of using microfluidic tests to investigate water-rock (mineral) interactions in fractures regarding sorption onto thin rock sections (i.e., shale and granite) of lead (Pb) and uranium (U) was evaluated using a synthetic PbCl 2 solution and uranium-containing natural groundwater as fluids. Effluent composition and element distribution on the thin rock sections before and after microfluidic testing were analyzed. Most Pb removal (9.8mg/cm 2 ) occurred within 3.5h (140 PVF), which was 74% of the total Pb removal (13.2mg/cm 2 ) at the end of testing (14.5h, 560 PVF). Element composition on the thin shale sections determined by μ-XRF analysis indicated that Pb removal was related primarily to Fe-containing minerals (e.g., pyrite). Two thin granite sections (biotite rich, Bt-R and biotite poor, Bt-P) exhibited no marked difference in uranium removal capacity, but a slightly higher amount of uranium was removed onto the thin Bt-R section (266μg/cm 2 ) than the thin Bt-P section (240μg/cm 2 ) within 120h (4800 PVF). However, uranium could not be detected by micro X-ray fluorescence (μ-XRF) analysis, likely due to the detection limit. These results suggest that microfluidic testing on thin rock sections enables quantitative evaluation of rock (mineral)-water interactions at the micro-fracture or pore scale. Copyright © 2016 Elsevier B.V. All rights reserved.

Carbonaceous Chondrite Thin Section Preparation

NASA Technical Reports Server (NTRS)

Harrington, R.; Righter, K.

2017-01-01

Carbonaceous chondrite meteorites have long posed a challenge for thin section makers. The variability in sample hardness among the different types, and sometimes within individual sections, creates the need for an adaptable approach at each step of the thin section making process. This poster will share some of the procedural adjustments that have proven to be successful at the NASA JSC Meteorite Thin Section Laboratory. These adjustments are modifications of preparation methods that have been in use for decades and therefore do not require investment in new technology or materials.

Synchrotron X-Ray Diffraction Analysis of Meteorites in Thin Section: Preliminary Results

NASA Technical Reports Server (NTRS)

Treiman, A. H.; Lanzirotti, A.; Xirouchakis, D.

2004-01-01

X-ray diffraction is the pre-eminent technique for mineral identification and structure determination, but is difficult to apply to grains in thin section, the standard meteorite preparation. Bright focused X-ray beams from synchrotrons have been used extensively in mineralogy and have been applied to extraterrestrial particles. The intensity and small spot size achievable in synchrotron X-ray beams makes them useful for study of materials in thin sections. Here, we describe Synchrotron X-ray Diffraction (SXRD) in thin section as done at the National Synchrotron Light Source, and cite examples of its value for studies of meteorites in thin section.

Benefit of computer-aided detection analysis for the detection of subsolid and solid lung nodules on thin- and thick-section CT.

PubMed

Godoy, Myrna C B; Kim, Tae Jung; White, Charles S; Bogoni, Luca; de Groot, Patricia; Florin, Charles; Obuchowski, Nancy; Babb, James S; Salganicoff, Marcos; Naidich, David P; Anand, Vikram; Park, Sangmin; Vlahos, Ioannis; Ko, Jane P

2013-01-01

The objective of our study was to evaluate the impact of computer-aided detection (CAD) on the identification of subsolid and solid lung nodules on thin- and thick-section CT. For 46 chest CT examinations with ground-glass opacity (GGO) nodules, CAD marks computed using thin data were evaluated in two phases. First, four chest radiologists reviewed thin sections (reader(thin)) for nodules and subsequently CAD marks (reader(thin) + CAD(thin)). After 4 months, the same cases were reviewed on thick sections (reader(thick)) and subsequently with CAD marks (reader(thick) + CAD(thick)). Sensitivities were evaluated. Additionally, reader(thick) sensitivity with assessment of CAD marks on thin sections was estimated (reader(thick) + CAD(thin)). For 155 nodules (mean, 5.5 mm; range, 4.0-27.5 mm)-74 solid nodules, 22 part-solid (part-solid nodules), and 59 GGO nodules-CAD stand-alone sensitivity was 80%, 95%, and 71%, respectively, with three false-positives on average (0-12) per CT study. Reader(thin) + CAD(thin) sensitivities were higher than reader(thin) for solid nodules (82% vs 57%, p < 0.001), part-solid nodules (97% vs 81%, p = 0.0027), and GGO nodules (82% vs 69%, p < 0.001) for all readers (p < 0.001). Respective sensitivities for reader(thick), reader(thick) + CAD(thick), reader(thick) + CAD(thin) were 40%, 58% (p < 0.001), and 77% (p < 0.001) for solid nodules; 72%, 73% (p = 0.322), and 94% (p < 0.001) for part-solid nodules; and 53%, 58% (p = 0.008), and 79% (p < 0.001) for GGO nodules. For reader(thin), false-positives increased from 0.64 per case to 0.90 with CAD(thin) (p < 0.001) but not for reader(thick); false-positive rates were 1.17, 1.19, and 1.26 per case for reader(thick), reader(thick) + CAD(thick), and reader(thick) + CAD(thin), respectively. Detection of GGO nodules and solid nodules is significantly improved with CAD. When interpretation is performed on thick sections, the benefit is greater when CAD marks are reviewed on thin rather than thick sections.

Rock Physics and Petrographic Parameters Relationship Within Siliciclastic Rocks: Quartz Sandstone Outcrop Study Case

NASA Astrophysics Data System (ADS)

Syafriyono, S.; Caesario, D.; Swastika, A.; Adlan, Q.; Syafri, I.; Abdurrokhim, A.; Mardiana, U.; Mohamad, F.; Alfadli, M. K.; Sari, V. M.

2018-03-01

Rock physical parameters value (Vp and Vs) is one of fundamental aspects in reservoir characterization as a tool to detect rock heterogenity. Its response is depend on several reservoir conditions such as lithology, pressure and reservoir fluids. The value of Vp and Vs is controlled by grain contact and contact stiffness, a function of clay mineral content and porosity also affected by mineral composition. The study about Vp and Vs response within sandstone and its relationship with petrographic parameters has become important to define anisotrophy of reservoir characteristics distribution and could give a better understanding about local diagenesis that influence clastic reservoir properties. Petrographic analysis and Vp-Vs calculation was carried out to 12 core sample which is obtained by hand-drilling of the outcrop in Sukabumi area, West Java as a part of Bayah Formation. Data processing and interpretation of sedimentary vertical succession showing that this outcrop comprises of 3 major sandstone layers indicating fluvial depositional environment. As stated before, there are 4 petrographic parameters (sorting, roundness, clay mineral content, and grain contact) which are responsible to the differences of shear wave and compressional wave value in this outcrop. Lithology with poor-sorted and well- roundness has Vp value lower than well-sorted and poor-roundness (sub-angular) grain. For the sample with high clay content, Vp value is ranging from 1681 to 2000 m/s and could be getting high until 2190 to 2714 m/s in low clay content sample even though the presence of clay minerals cannot be defined neither as matrix nor cement. The whole sample have suture grain contact indicating telogenesis regime whereas facies has no relationship with Vp and Vs value because of the different type of facies show similar petrographic parameters after diagenesis.

Preliminary study of a potential CO2 reservoir area in Hungary

NASA Astrophysics Data System (ADS)

Sendula, Eszter; Király, Csilla; Szabó, Zsuzsanna; Falus, György; Szabó, Csaba; Kovács, István; Füri, Judit; Kónya, Péter; Páles, Mariann; Forray, Viktória

2014-05-01

Since the first international agreement in 1997 (the Kyoto Protocol) the reduction of greenhouse gas emission has a key role in the European Union's energy and climate change policy. Following the Directive 2009/31/EC we are experiencing a significant change in the Hungarian national activity. Since the harmonization procedure, which was completed in May 2012, the national regulation obligates the competent authority to collect and regularly update all geological complexes that are potential for CO2 geological storage. In Hungary the most abundant potential storage formations are mostly saline aquifers of the Great Hungarian Plain (SE-Hungary), with sandstone reservoir and clayey caprock. The Neogene basin of the Great Hungarian Plain was subsided and then filled by a prograding delta system from NW and NE during the Late Miocene, mostly in the Pannonian time. The most potential storage rock was formed as a fine-grained sandy turbidite interlayered by thin argillaceous beds in the deepest part of the basin. It has relatively high porosity, depth and more than 1000 m thickness. Providing a regional coverage for the sandy turbidite, a 400-500 m thick argillaceous succession was formed in the slope environment. The composition, thickness and low permeability is expected to make it a suitable, leakage-safe caprock of the storage system. This succession is underlain by argillaceous rocks that were formed in the basin, far from sediment input and overlain by interfingering siltstone, sandstone and claystone succession formed in delta and shoreline environments and in the alluvial plain. Core samples have been collected from the potential reservoir rock and its cap rock in the Great Hungarian Plain's succession. The water compositions of the studied depth were known from well-log database. Using the information, acquired from these archive documents, we have constructed input data for geochemical modeling in order to to study the effect of pCO2 injection in the potential CO2 storage environment. From the potential reservoir rock samples (sandstone) thin sections were prepared to determine the mineral composition, pore distribution, pore geometry and grain size. The volume ratio of the minerals was calculated using pixel counter. To have more accurate mineral composition, petrographic observation and SEM analyzes have been carried out. The caprock samples involved in the study can be divided into mudstone and aleurolite samples. To determine the mineral composition of these samples, XRD, DTA, FTIR, SEM analysis has been carried out. To obtain a picture about the geochemical behavior of the potential CO2 storage system, geochemical models were made for the reservoir rocks. For the equilibrium geochemical model, PHREEQC 3.0 was used applying LLNL database. The data used in the model are real pore water compositions from the studied area and an average mineral composition based on petrographic microscope and SEM images. In the model we considered the cation-anion ratio (<10%) and the partial pressure of CO2. First of all, we were interested in the direction of the geochemical reactions during an injection process. Present work is focused on the mineralogy of the most potential storage rock and its caprock, and their expectable geochemical reactions for the effect of scCO2.

Systematics of melt stagnation in peridotites from the Godzilla Megamullion

NASA Astrophysics Data System (ADS)

Loocke, M.; Snow, J. E.; Ohara, Y.

2010-12-01

The Godzilla Megamullion (GM) Massif is the largest known example of an Oceanic Core Complex (OCC) or the exhumed footwall of a low angle-large offset oceanic detachment fault. It lies on the extinct Parece Vela Rift spreading center within the Parece Vela Back-arc Basin of the Philippine Sea. This has thus allowed for sampling of a young back-arc mantle section. Sampling of the massif has returned a dominantly ultramafic lithology, divided petrographically into depleted, fertile, and melt-percolated groups (1). Petrographic analysis of the extant peridotite thin section collection found that 44% of all GM peridotites (71 out of 161) exhibit evidence of plagioclase impregnation compared to the worldwide abyssal peridotite average of ~20% (2). The mullion is divided up into three regions, the proximal region ( closest to termination of spreading), the medial region, and the distal region (furthest from the termination of spreading)(3).Observations by region provide that 53% ( 62 out of 116 samples) in the proximal region (15 dredges), 12% ( 2 out of 17 samples) in the medial mullion (3 dredges), and 25% (7 out of 28) in the distal mullion (5 dredges) show of evidence of plagioclase impregnation (4). Major element analyses of spinels were completed using the Cameca SX-50 Electron Microprobe facility at the University of Houston. The Cr# [100 x Cr/(Cr + Al)] ranges from 10 to 65 with TiO2 concentrations ranging from less than 0.01 up to 1.6 wt%. When the Cr#s of the samples are plotted along the massif, a pattern of melt depletion exists that is consistent with the degree of plagioclase impregnation. In the distal region, Cr#s start at around an average of 35 and range up to 65 for melt percolated samples. In the medial region, a drop off in Cr# of about 1 Cr# per kilometer is observed with the trend bottoming out at around a Cr# of 10. In the proximal region, Cr#s closer to the medial region are observed as having more fertile values of around 20 but are found amongst melt-impregnated samples with values ranging up to 50. This range is seen as having increasing minimum and maximum values with distance away from the medial section until it reaches its peak at a base Cr# of 30 with a maximum of 65. From this trend, a general model for the secular evolution of the GM mantle section can be established (5). The ridge segment experienced normal mid-oceanic ridge growth with robust mantle melting during the time period represented by the distal region. At the boundary to the medial region, a steep drop-off in melt productivity was experienced, leading to minimal mantle melting during the time period represented by the medial region. Soon thereafter, melting began again, but was trapped in a thickened and cooling lithosphere, causing the melt to pool and react with its host peridotite. (1) Ohara, et al., (2003) G3. 4 (7), 8611, 10.1029/2002GC000469. (2) Dick (1989) Geol Soc. Lond. Spec. Pub. 42:71-105. (3) Ohara, et al., (2009), Eos Trans. AGU, 90(52), Fall Meet. Suppl. Abst.Num. T33D-06 (4) Loocke, et al., (2009), Eos Trans. AGU, 90(52), Fall Meet. Suppl. Abst.Num. T21A-1776 (5) Snow, et al., (2009), Eos Trans. AGU, 90(52), Fall Meet. Suppl. Abst.Num. T33D-07

Tectono-metamorphic evolution of the Kibuye-Gitarama-Gatumba area (Rwanda): using petrochronology to unravel the geodynamic framework of the Karagwe-Ankole Belt

NASA Astrophysics Data System (ADS)

Van Daele, Johanna; Jacques, Dominique; Hulsbosch, Niels; Dewaele, Stijn; Muchez, Philippe

2017-04-01

The Mesoproterozoic Karagwe-Ankole Belt (KAB) extends from Burundi over Rwanda and NW-Tanzania to S-Uganda (Central Africa). The integration of the metamorphic and magmatic evolution of this orogenic belt in a consistent geodynamic framework is still controversial. Additionally, geochronological information on the deformation phases is limited. This tectono-metamorphic model is, however, a crucial component in the understanding of the Meso- to Early Neoproterozoic mineralization processes. A detailed structural mapping of road and river transects was performed in the Kibuye-Gitarama-Gatumba area (West Rwanda) to determine the deformation history of the KAB. Structural analyses and petrographic studies identified two main compressive deformation phases. A locally observed foliation with a N45W-N50W orientation is interpreted as the consequence of a first compressional phase (D1, shortening direction N40E-N45E). Additionally, a well-developed crenulation cleavage and a regionally pervasive foliation were found. The cleavage and foliation have an orientation of N20W-N30W (exceptionally N20E) and are indicative of a second compressional phase (D2) with an EW shortening direction. Final extension (D3) along a N30W-N10E direction resulted in boudinage and joint development. Fieldwork observations combined with known ages of the granites in the KAB indicate that D1 and D2 took place prior to 986 Ma while D3 is younger than 986 Ma. Based on thin section petrography, a petrochronological strategy was outlined to fill in the gaps of the currently broadly defined timeframe. The regional metamorphic grade of the study area is upper greenschist, with the formation of muscovite, biotite, chlorite, garnet, staurolite and cordierite. The main penetrative tectonic foliations (D1 and D2) are expressed by the preferential orientation of muscovite or biotite. In some cases, muscovite growing along the crenulation cleavage (syn-D2) was observed. Furthermore, pre- and syn-D2 garnets were identified. Different generations of quartz veins (post-dating D3) contain muscovite, garnet and/or biotite. These minerals provide excellent dating possibilities (Ar-Ar, in-situ Rb-Sr and Sm-Nd). The obtained results will be used to refine the chronological aspects of the deformation history of the KAB. Furthermore, these data will be combined with regional structural data, petrographic and geothermobarometric analyses to reconstruct the tectono-metamorphic evolution of the Karagwe-Ankole Belt, which will allow to obtain a better insight in the geodynamic evolution and the ore-forming processes.

Inside the volcano: The how and why of Thrihnukagigur volcano, Iceland

NASA Astrophysics Data System (ADS)

LaFemina, Peter; Hudak, Michael; Feineman, Maureen; Geirsson, Halldor; Normandeau, Jim; Furman, Tanya

2015-04-01

The Thrihnukagigur volcano, located in the Brennisteinsfjöll fissure swarm on the Reykjanes Peninsula, Iceland, offers a unique exposure of the upper magmatic plumbing system of a monogenetic volcano. The volcano formed during a dike-fed strombolian eruption ~3500 BP with flow-back leaving an evacuated conduit, elongated parallel to the regional maximum horizontal stress. At least two vents were formed above the dike, as well as several small hornitos south-southwest of the main vent. In addition to the evacuated conduit, a cave exists 120 m below the vent. The cave exposes stacked lava flows and a buried cinder cone. The unconsolidated tephra of the cone is cross-cut by a NNE-trending dike, which runs across the ceiling of this cave to the vent that produced lava and tephra during the ~3500 BP fissure eruption. We present geochemical, petrologic and geologic observations, including a high-resolution three-dimensional scan of the system that indicate the dike intersected, eroded and assimilated unconsolidated tephra from the buried cinder cone, thus excavating a region along the dike, allowing for future slumping and cave formation. Two petrographically distinct populations of plagioclase phenocrysts are present in the system: a population of smaller (maximum length 1 mm) acicular phenocrysts and a population of larger (maximum length 10 mm) tabular phenocrysts that is commonly broken and displays disequilibrium sieve textures. The acicular plagioclase crystals are present in the dike and lavas while the tabular crystals are in these units and the buried tephra. An intrusion that appears not to have interacted with the tephra has only acicular plagioclase. This suggests that a magma crystallizing a single acicular population of plagioclase intruded the cinder cone and rapidly assimilated the tephra, incorporating the tabular population of phenocrysts from the cone. Petrographic thin-sections of lavas sampled near the vent show undigested fragments of tephra from the cone. This conceptual model for basaltic cannibalism is supported by field observations of large-scale erosion upward into the tephra, which is coated by magma flow-back indicating that magma was involved in the physical erosion of the tephra. Whole rock major and trace element geochemical data are consistent with this model of mixing between the intruded magma and the tephra. While the unique exposure at Thrihnukagigur makes it an exceptional place to investigate basaltic cannibalism, we suggest that it is not limited to this volcanic system. Rather it is a process that likely occurs throughout Iceland and may contribute to the evolution of the crust in other predominately basaltic settings.

A basin on an unstable ground: Correlation of the Middle Archaean Moodies Basin, Barberton Greenstone Belt, South Africa

NASA Astrophysics Data System (ADS)

Ohnemueller, Frank; Heubeck, Christoph; Kirstein, Jens; Gamper, Antonia

2010-05-01

The 3.22 Ga-old Moodies Group, representing the uppermost part of the Barberton Supergroup of the Barberton Greenstone Belt (BGB), is the oldest well-exposed, relatively unmetamorphosed, quartz-rich sedimentary unit on Earth. Moodies facies (north of the Inyoka Fault) were thought to be largely of alluvial, fluvial, deltaic or shallow-marine origin (Anhaeusser, 1976; Eriksson, 1980; Heubeck and Lowe, 1994) and in its upper part syndeformational. However, units can only locally be correlated, and the understanding of the interplay between Moodies sedimentation and deformation is thus limited. We mapped and measured Moodies units in the northern BGB. They partly consist of extensive turbiditic deepwater deposits, including graded bedding, flame structures, and slumped beds, interbedded with jaspilites. These contrast with shallow-water environments, south-facing progressive unconformities and overlying alluvial-fan conglomerates along the northern margin of the Saddleback Syncline further south. The palaeogeographic setting in which late BGB deformation was initiated therefore appears complex and cannot be readily explained by a simple southward-directed shortening event. In order to constrain Moodies basin setting before and during late-Moodies basin collapse, we correlated ~15 measured sections in the northern and central BGB. Most units below the Moodies Lava (MdL, ca. 3230.6+-6 Ma) can be correlated throughout although facies variations are apparent. Above the Moodies Lava, coarse-grained units can only be correlated through the Eureka Syncline and the Moodies Hills Block but not with the Saddleback Syncline. Fine-grained and jaspilitic units can be correlated throughout the northern BGB. Moodies below-wavebase deposition occurred largely north of the Saddleback Fault. The observations are consistent with a pronounced basin compartmentalization event following the eruption of the MdL which appeared to have blanketed most of the Moodies basin(s) in middle Moodies time and immediately predates the initiation of basin shortening. Basin compartmentalization was likely due to the movement along a group of major faults (Sheba, Haki, Barbrook, Saddleback Faults) between the present Saddleback and Eureka Synclines, creating at least two subbasins in late Moodies time. Even though sediment provenance thus became localized, intensive Archaean weathering likely contributed to generate petrographically similar quartz-rich sandstones in fault-bounded minibasins. The late-Moodies minibasins may have become connected occasionally, allowing concurrent deposition of thin BIFs. A similar phase of movement along the major transcurrent Inyoka Fault may be responsible for the distinct petrographic character of Moodies sandstones south of that fault.

Preliminary petrographic description and geologic implications of the Apollo 17 Station 7 boulder consortium samples

USGS Publications Warehouse

Chao, E.C.T.; Minkin, J.A.; Thompson, C.L.

1974-01-01

Preliminary petrographic description and mineral composition of four hand samples (77135, 77115, 77075 and 77215) are presented. 77135, 77115, and 77075 all crystallized from fragment-laden melts; they are similar in textures but differ in grain size. 77135 and 77115 are pigeonite feldspathic basalts. On the basis of geologic and petrographic evidence, 77115 and 77075 are related; they formed, cooled, and consolidated before being engulfed in the vesicular 77135. The impact or igneous origin of the melts from which these rocks crystallized cannot be determined. 77215 is a shocked, strongly sheared and granulated microbreccia consisting of three major lithologies dominated by mineral clasts of orthopyroxene and calcic plagioclase. The orthopyroxene clasts contain coarse exsolved blebs of augite, suggesting a deep-seated origin. The major, minor, and trace element compositions of 77135, 77115, and 77075 are in general similar. They represent a major highland rock type, perhaps more important than anorthosites. ?? 1974.

Application of petrographic examination techniques to the assessment of fire-damaged concrete and masonry structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ingham, Jeremy P., E-mail: inghamjp@halcrow.com

The number of building fires has doubled over the last 50 years. There has never been a greater need for structures to be assessed for fire damage to ensure safety and enable appropriate repairs to be planned. Fortunately, even after a severe fire, concrete and masonry structures are generally capable of being repaired rather than demolished. By allowing direct examination of microcracking and mineralogical changes, petrographic examination has become widely used to determine the depth of fire damage for reinforced concrete elements. Petrographic examination can also be applied to fire-damaged masonry structures built of materials such as stone, brick andmore » mortar. Petrography can ensure accurate detection of damaged geomaterials, which provides cost savings during building repair and increased safety reassurance. This paper comprises a review of the role of petrography in fire damage assessments, drawing on a range of actual fire damage investigations.« less

Gallery of melt textures developed in Westerly Granite during high-pressure triaxial friction experiments

USGS Publications Warehouse

Moore, Diane E.; Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M.

2016-09-23

IntroductionMelting occurred during stick-slip faulting of granite blocks sheared at room-dry, room-temperature conditions in a triaxial apparatus at 200–400 megapascals (MPa) confining pressure. Petrographic examinations of melt textures focused largely on the 400-MPa run products. This report presents an overview of the petrographic data collected on those samples, followed by brief descriptions of annotated versions of all the images.Scanning electron microscope (SEM) images of the starting materials and the three examined 400-MPa samples are presented in this report. Secondary-electron (SE) and backscattered-electron (BSE) imaging techniques were used on different samples. The SE images look down on the sawcut surfaces, yielding topographic and three-dimensional textural information. The BSE imaging was done on samples cut to provide cross-sectional views of the glass-filled shear band (or zone) that developed along the sawcut. Brightness in the BSE images increases with increasing mean atomic number of the material. Additional chemical information about the quenched melt and adjoining minerals was obtained using the energy dispersive system of the SEM during BSE examinations. However, the very narrow shear-band thicknesses and common occurrence of very fine lamellar compositional layering limited the usefulness of this technique for estimating melt chemistry.

Reservoir heterogeneity in Carter Sandstone, North Blowhorn Creek oil unit and vicinity, Black Warrior Basin, Alabama

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kugler, R.L.; Pashin, J.C.

1992-05-01

This report presents accomplishments made in completing Task 3 of this project which involves development of criteria for recognizing reservoir heterogeneity in the Black Warrior basin. The report focuses on characterization of the Upper Mississippian Carter sandstone reservoir in North Blowhorn Creek and adjacent oil units in Lamar County, Alabama. This oil unit has produced more than 60 percent of total oil extracted from the Black Warrior basin of Alabama. The Carter sandstone in North Blowhorn Creek oil unit is typical of the most productive Carter oil reservoirs in the Black Warrior basin of Alabama. The first part of themore » report synthesizes data derived from geophysical well logs and cores from North Blowhorn Creek oil unit to develop a depositional model for the Carter sandstone reservoir. The second part of the report describes the detrital and diagenetic character of Carter sandstone utilizing data from petrographic and scanning electron microscopes and the electron microprobe. The third part synthesizes porosity and pore-throat-size-distribution data determined by high-pressure mercury porosimetry and commercial core analyses with results of the sedimentologic and petrographic studies. The final section of the report discusses reservoir heterogeneity within the context of the five-fold classification of Moore and Kugler (1990).« less

Petrography, geochemistry and palynology of the Stockton coal bed (Middle Pennsylvanian), Martin County, Kentucky

USGS Publications Warehouse

Hower, J.C.; Eble, C.F.; Pierce, B.S.

1996-01-01

The Middle Pennsylvanian (Westphalian D) Stockton (also known as the Broas) coal bed of the Breathitt Formation is an important energy resource in Kentucky. Petrographic, geochemical and palynologic studies were undertaken from mine, core and highway exposures in Martin and northern Pike counties, Kentucky, in order to determine the influence of the Stockton depositional ecosystem on those parameters. Vitrinite-rich Stockton lithotypes are dominated by Lycospora. Dull lithotypes, including both high- and low-ash yield durains, generally have abundant Densosporites, suggesting that the parent plant inhabited a fairly wide range of environments. Lithologies having tree ferns as an important component also have high fusinite + semifusinite and a low telinite/gelocollinite ratio. The aerial root bundles of the tree ferns were susceptible to oxidation and, for tissue not oxidized to inertinite, to preservation as gelocollinite. In the initial stages of formation, the Stockton mire was discontinuous and had a rather restricted floral assemblage. The presence of durains higher in the Stockton section, particularly the low-ash yield durains having petrographic indicators of degradation, suggests that portions of the mire developed as a domed peat. The termination of the mire as a high-sulfur, arboreous lycopod-domimated mire is consistent with the return to more planar mire development.

Petrographic Evidence for Rapid Heating and Cooling During Chrondrule Formation

NASA Technical Reports Server (NTRS)

Wasson, J. T.

2004-01-01

The chondrule cooling rates used in most chondrule-formation models appear to be too low. Recent petrographic evidence indicates that the amount of crystal (especially olivine) growth that occurred after the last melting event was about 30 smaller than the grain sizes simulated in order to estimate cooling rates. The smaller amount of growth leads to an upwards revision of cooling rates by about a factor of 1000. Most chondrules are porphyritic. They consist of large and small crystals of olivine and, less commonly, pyroxene immersed in a mesostasis having a plagioclase-rich composition. In the most primitive chondrites the mesostasis is often vitreous. Because the large majority of chondrules contain FeS, it is clear that the nebula had cooled below the FeS condensation temperature (ca. 650 K) before chondrule formation occurred. The high FeO/(FeO+MgO) ratios of some chondrules require still lower nebular temperatures (less than 500 K). The traditional view has been that porphyritic chondrules formed in a single heating/cooling event and many laboratory experiments have been carried out in various kinds of kinds of furnaces to try to simulate the formation of chondrules textures in a single heating/cooling cycle. These furnace experiments have been used to infer the cooling rates of chondrules during the temperature range at which olivine crystallized from the melt. Most of these inferred values are in the range 0.01-1 K per second. These low cooling rates are problematical because there is no long-term nebular environment that yields such values. In transparent regions chondrules would cool at rates orders of magnitude higher, whereas in an opaque nebular disk the cooling rates would be many orders of magnitude lower. And these latter conditions are not suitable locations for chondrule formation because such high temperatures would cause the complete evaporation of chondrules (which have melting temperatures about 600 K higher than their evaporation temperatures). During the last several years several kinds of petrographic evidence indicating rapid chondrule cooling have been recognized. These include thin overgrowths on relict grains, clusters of small crystals that grew following the most recent melting event, and fragments preserving shardlike shapes that would have been hidden had several tens of micrometers of new growth occurred following the last melting event. And there are other indications of rapid cooling including the preservation of volatiles such as FeS and one case where the modeling of O-isotopic and FeO/(FeO+MgO) gradients indicated a high cooling rate.

Thin sectioning and surface replication of ice at low temperature.

USGS Publications Warehouse

Daley, M.A.; Kirby, S.H.

1984-01-01

We have developed a new technique for making thin sections and surface replicas of ice at temperatures well below 273d K. The ability to make thin sections without melting sample material is important in textural and microstructural studies of ice deformed at low temperatures because of annealing effects we have observed during conventional section making.-from Author

Student Use of Thin Sections in Introductory Geology

ERIC Educational Resources Information Center

O'Brien, Lawrence

1978-01-01

Thin-section photomicrographs are used to introduce the introductory geology laboratory classes to many of the optical properties of minerals. Evaluation by questionnaire suggests that the study of thin sections has a positive effect on the enjoyment and understanding of rock identification and classification by introductory students. (Author/MA)

Publications - GMC 391 | Alaska Division of Geological & Geophysical

Science.gov Websites

DGGS GMC 391 Publication Details Title: Core descriptions, photographs and thin section photomicro , Inc., 2010, Core descriptions, photographs and thin section photomicro-graphs from the Humble Oil DDH DVD. Keywords Core Drilling; Thin Section Top of Page Department of Natural Resources, Division of

Comparison of the petrography, palynology and paleobotany of the Stockton coal bed, West Virginia and implications for paleoenvironmental interpretations

USGS Publications Warehouse

Pierce, B.S.; Stanton, R.W.; Eble, C.F.

1993-01-01

The Stockton coal bed (Middle Pennsylvanian) is a relatively high ash coal composed primarily of moderately thin banded, sparsely thin banded, and nonbanded coal (splint and cannel coal). Comparisons of petrographic, palynologic, and paleobotanic data gathered from the same sample sets from a single column of the Stockton coal bed indicate that compositional correspondences among the sets exist regardless of coal type. Some correspondences are believed to exist because of original plant constituents and others because of the paleoenvironment of peat formation. Using some combination of these data is critical when interpreting paleoenvironmental conditions because (1) a direct correspondence is lacking between many of the data and (2) each of the three data sets provides a unique and important perspective on the paleomire. The Stockton paleomire in the area of this study supported a diverse flora that consisted of both small and arboreous lycopsids, small ferns and tree ferns, calamites, cordaites, and pteridosperms. There appear to have been two successions of Lycospora spore-dominated, vitrinite-rich, liptinite-poor peat formation, which were followed by inertinite-rich peat formation marked by a tree fern-dominant spore assemblage and abundant unidentifiable plant tissues. These are interpreted to be two water-laden or topogenous peat formational stages followed by slightly domed, better drained peat formation. ?? 1993.

The end-Permian regression in the western Tethys: sedimentological and geochemical evidence from offshore the Persian Gulf, Iran

NASA Astrophysics Data System (ADS)

Tavakoli, Vahid; Naderi-Khujin, Mehrangiz; Seyedmehdi, Zahra

2018-04-01

Detailed sedimentological and geochemical records across the Permian-Triassic boundary (PTB) in five offshore wells of the central Persian Gulf served to interpret the end-Permian sea-level change in this region. A decrease in sea level at the PTB was established by petrographical and geochemical study of the boundary. Thin sections showed that Upper Permian strata are composed of dolomite with minor anhydrite, changing into limestone in Lower Triassic sediments. Brine dilution toward the boundary supports sea-level fall in the Permian-Triassic transition, reflected by a decrease in anhydrite content and a shallowing-upward trend from lagoonal to peritidal facies. Isotopic changes at the boundary are in favor of sea-level fall. Changes in both carbon (from about 4 to -1‰) and oxygen (from 2 to -5‰) stable isotopes show negative excursions. The shift in carbon isotope values is a global phenomenon and is interpreted as resulting from carbonate sediment interaction with 12C-rich waters at the end-Permian sea-level fall. However, the oxygen isotope shift is attributed to the effect of meteoric waters with negative oxygen isotope values. The increase in strontium isotope ratios is also consistent with the high rate of terrestrial input at the boundary. The effect of meteoric conditions during diagenesis is evident from vuggy and moldic porosities below the PTB. The following transgression at the base of the Triassic is evident from the presence of reworked fossils and intraclasts resulting from deposition from agitated water.

SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions

NASA Astrophysics Data System (ADS)

Schopf, J. William; Kitajima, Kouki; Spicuzza, Michael J.; Kudryavtsev, Anatoliy B.; Valley, John W.

2018-01-01

Analyses by secondary ion mass spectroscopy (SIMS) of 11 specimens of five taxa of prokaryotic filamentous kerogenous cellular microfossils permineralized in a petrographic thin section of the ˜3,465 Ma Apex chert of northwestern Western Australia, prepared from the same rock sample from which this earliest known assemblage of cellular fossils was described more than two decades ago, show their δ13C compositions to vary systematically taxon to taxon from ‑31‰ to ‑39‰. These morphospecies-correlated carbon isotope compositions confirm the biogenicity of the Apex fossils and validate their morphology-based taxonomic assignments. Perhaps most significantly, the δ13C values of each of the five taxa are lower than those of bulk samples of Apex kerogen (‑27‰), those of SIMS-measured fossil-associated dispersed particulate kerogen (‑27.6‰), and those typical of modern prokaryotic phototrophs (‑25 ± 10‰). The SIMS data for the two highest δ13C Apex taxa are consistent with those of extant phototrophic bacteria; those for a somewhat lower δ13C taxon, with nonbacterial methane-producing Archaea; and those for the two lowest δ13C taxa, with methane-metabolizing γ-proteobacteria. Although the existence of both methanogens and methanotrophs has been inferred from bulk analyses of the carbon isotopic compositions of pre-2,500 Ma kerogens, these in situ SIMS analyses of individual microfossils present data interpretable as evidencing the cellular preservation of such microorganisms and are consistent with the near-basal position of the Archaea in rRNA phylogenies.

Pore network quantification of sandstones under experimental CO2 injection using image analysis

NASA Astrophysics Data System (ADS)

Berrezueta, Edgar; González-Menéndez, Luís; Ordóñez-Casado, Berta; Olaya, Peter

2015-04-01

Automated-image identification and quantification of minerals, pores and textures together with petrographic analysis can be applied to improve pore system characterization in sedimentary rocks. Our case study is focused on the application of these techniques to study the evolution of rock pore network subjected to super critical CO2-injection. We have proposed a Digital Image Analysis (DIA) protocol that guarantees measurement reproducibility and reliability. This can be summarized in the following stages: (i) detailed description of mineralogy and texture (before and after CO2-injection) by optical and scanning electron microscopy (SEM) techniques using thin sections; (ii) adjustment and calibration of DIA tools; (iii) data acquisition protocol based on image capture with different polarization conditions (synchronized movement of polarizers); (iv) study and quantification by DIA that allow (a) identification and isolation of pixels that belong to the same category: minerals vs. pores in each sample and (b) measurement of changes in pore network, after the samples have been exposed to new conditions (in our case: SC-CO2-injection). Finally, interpretation of the petrography and the measured data by an automated approach were done. In our applied study, the DIA results highlight the changes observed by SEM and microscopic techniques, which consisted in a porosity increase when CO2 treatment occurs. Other additional changes were minor: variations in the roughness and roundness of pore edges, and pore aspect ratio, shown in the bigger pore population. Additionally, statistic tests of pore parameters measured were applied to verify that the differences observed between samples before and after CO2-injection were significant.

SIMS analyses of the oldest known assemblage of microfossils document their taxon-correlated carbon isotope compositions.

PubMed

Schopf, J William; Kitajima, Kouki; Spicuzza, Michael J; Kudryavtsev, Anatoliy B; Valley, John W

2018-01-02

Analyses by secondary ion mass spectroscopy (SIMS) of 11 specimens of five taxa of prokaryotic filamentous kerogenous cellular microfossils permineralized in a petrographic thin section of the ∼3,465 Ma Apex chert of northwestern Western Australia, prepared from the same rock sample from which this earliest known assemblage of cellular fossils was described more than two decades ago, show their δ 13 C compositions to vary systematically taxon to taxon from -31‰ to -39‰. These morphospecies-correlated carbon isotope compositions confirm the biogenicity of the Apex fossils and validate their morphology-based taxonomic assignments. Perhaps most significantly, the δ 13 C values of each of the five taxa are lower than those of bulk samples of Apex kerogen (-27‰), those of SIMS-measured fossil-associated dispersed particulate kerogen (-27.6‰), and those typical of modern prokaryotic phototrophs (-25 ± 10‰). The SIMS data for the two highest δ 13 C Apex taxa are consistent with those of extant phototrophic bacteria; those for a somewhat lower δ 13 C taxon, with nonbacterial methane-producing Archaea; and those for the two lowest δ 13 C taxa, with methane-metabolizing γ-proteobacteria. Although the existence of both methanogens and methanotrophs has been inferred from bulk analyses of the carbon isotopic compositions of pre-2,500 Ma kerogens, these in situ SIMS analyses of individual microfossils present data interpretable as evidencing the cellular preservation of such microorganisms and are consistent with the near-basal position of the Archaea in rRNA phylogenies.

High Throughput Petrochronology and Sedimentary Provenance Analysis by Automated Phase Mapping and LAICPMS

NASA Astrophysics Data System (ADS)

Vermeesch, Pieter; Rittner, Martin; Petrou, Ethan; Omma, Jenny; Mattinson, Chris; Garzanti, Eduardo

2017-11-01

The first step in most geochronological studies is to extract dateable minerals from the host rock, which is time consuming, removes textural context, and increases the chance for sample cross contamination. We here present a new method to rapidly perform in situ analyses by coupling a fast scanning electron microscope (SEM) with Energy Dispersive X-ray Spectrometer (EDS) to a Laser Ablation Inductively Coupled Plasma Mass Spectrometer (LAICPMS) instrument. Given a polished hand specimen, a petrographic thin section, or a grain mount, Automated Phase Mapping (APM) by SEM/EDS produces chemical and mineralogical maps from which the X-Y coordinates of the datable minerals are extracted. These coordinates are subsequently passed on to the laser ablation system for isotopic analysis. We apply the APM + LAICPMS method to three igneous, metamorphic, and sedimentary case studies. In the first case study, a polished slab of granite from Guernsey was scanned for zircon, producing a 609 ± 8 Ma weighted mean age. The second case study investigates a paragneiss from an ultra high pressure terrane in the north Qaidam terrane (Qinghai, China). One hundred seven small (25 µm) metamorphic zircons were analyzed by LAICPMS to confirm a 419 ± 4 Ma age of peak metamorphism. The third and final case study uses APM + LAICPMS to generate a large provenance data set and trace the provenance of 25 modern sediments from Angola, documenting longshore drift of Orange River sediments over a distance of 1,500 km. These examples demonstrate that APM + LAICPMS is an efficient and cost effective way to improve the quantity and quality of geochronological data.

Mineralogy of Nicobar Fan turbidites (IODP Leg 362): Himalayan provenance and diagenetic control.

NASA Astrophysics Data System (ADS)

Limonta, M.; Garzanti, E.; Ando, S.; Carter, A.; Milliken, K. L.; Pickering, K. T.

2017-12-01

In this study we use quantitative petrographic and heavy-mineral data on silt-sized and sand-sized sediments from the Nicobar Fan turbiditic depositional system to unravel their provenance and discriminate between pre-depositional and post-depositional processes controlling sediment mineralogy. Eighteen samples from the two drill sites U1480 e U1481, collected down to a depth of 1400 m during International Ocean Discovery Expedition 362, were selected for analysis. A complete section of the sedimentary section overlying oceanic basaltic basement was recovered at the U1480 drill site, whereas the U1481 drill site, located 35 km to the southeast, focused on the deeper interval of the sedimentary section overlying oceanic basement. Here we illustrate the compositional trends observed throughout the recovered succession, and compare heavy-mineral suites characterizing sediments drilled at the two U1480 and U1481 sites to check for potential differences in sediment provenance over a relatively short distance in trench settings. Diagenetic control with increasing burial depth was also specifically investigated. In Pleistocene sediments at depths of a few tens of meters only, rich heavy-mineral assemblages include mainly hornblende, epidote, and garnet, associated with apatite, clinopyroxene, tourmaline, sillimanite, kyanite, zircon, titanite, and rare staurolite and rutile, testifying to long-distance provenance from the Himalayan range via the Ganga-Brahmaputra fluvio-deltaic-turbiditic system. Heavy-mineral concentration shows a progressive decrease with burial depth, pointing to selective diagenetic dissolution of less durable detrital minerals. Clinopyroxene becomes rare below 400 m depth and was not recorded below 500 m depth, where amphibole decreases notably in relative abundance. More durable heavy minerals, including zircon, tourmaline, apatite, garnet and epidote, consequently tend to be relatively enriched with increasing age and burial depth. Petrographic and heavy-mineral data, combined with biostratigraphic, paleomagnetic, and geochemical evidence, allow us to unravel the sedimentary history of the Nicobar Fan as related to Himalayan uplift, erosion, and monsoon development during the last 10 Ma.

Rock Magnetic Study of IODP/ICDP Expedition 364 Site M0077A Drill Cores: Post-Impact Sediments, Impact Breccias, Melt, Granitic Basement and Dikes

NASA Astrophysics Data System (ADS)

Fucugauchi, J. U.; Perez-Cruz, L. L.; Rebolledo-Vieyra, M.; Tikoo, S.; Zylberman, W.; Lofi, J.

2017-12-01

Drilling at Site M0077 sampled post-impact sediments overlying a peak ring consisting of impact breccias, melt rock and granitoids. Here we focus on characterizing the peak ring using magnetic properties, which vary widely and depend on mineralogy, depositional and emplacement conditions and secondary alterations. Rock magnetic properties are integrated with Multi-Sensor Core Logger (MSCL) data, vertical seismic profile, physical properties, petrographic and chemical analyses and geophysical models. We measure low-field magnetic susceptibility at low- and high-frequencies, intensity and direction of natural remanent magnetization (NRM) and laboratory-induced isothermal (IRM) and anhysteretic (ARM) magnetizations, alternating-field demagnetization of NRM, IRM and NRM, susceptibility variation with temperature, anisotropy of magnetic susceptibility, hysteresis and IRM back-field demagnetization. Post-impact carbonates show low susceptibilities and NRM intensities, variable frequency-dependent susceptibilities and multivectorial remanences residing in low and high coercivity minerals. Hysteresis loops show low coercivity saturation magnetizations and variable paramagnetic mineral contents. Impact breccias (suevites) and melt rock show higher susceptibilities, low frequency-dependent susceptibilities, high NRM, ARM and IRM intensities and moderate ARM intensity/susceptibility ratios. Magnetic signal is dominated by fine-grained magnetite and titanomagnetites with PSD domain states. Melt rocks at the base of impactite section show the highest susceptibilities and remanence intensities. Basement section is characterized by low susceptibilities in the granites and higher values in the dikes, with NRM and ARM intensities increasing towards the base. The high susceptibilities and remanence intensities correlate with high seismic velocities, density and decreased porosity and electrical resistivity. Fracturing and alteration account for the reduced seismic velocities, density and magnetic properties in the basement section. Site M0077 is in a horizontal gradient high within the semi-circular gravity low in the crater central zone. Correlation with MSCL logs and petrographic and chemical data will allow further detailed characterization of peak ring units.

Estimating pore and cement volumes in thin section

USGS Publications Warehouse

Halley, R.B.

1978-01-01

Point count estimates of pore, grain and cement volumes from thin sections are inaccurate, often by more than 100 percent, even though they may be surprisingly precise (reproducibility + or - 3 percent). Errors are produced by: 1) inclusion of submicroscopic pore space within solid volume and 2) edge effects caused by grain curvature within a 30-micron thick thin section. Submicroscopic porosity may be measured by various physical tests or may be visually estimated from scanning electron micrographs. Edge error takes the form of an envelope around grains and increases with decreasing grain size and sorting, increasing grain irregularity and tighter grain packing. Cements are greatly involved in edge error because of their position at grain peripheries and their generally small grain size. Edge error is minimized by methods which reduce the thickness of the sample viewed during point counting. Methods which effectively reduce thickness include use of ultra-thin thin sections or acetate peels, point counting in reflected light, or carefully focusing and counting on the upper surface of the thin section.

Petrographic microscope investigation of mortar and ceramic technologies for the conservation of the built heritage

NASA Astrophysics Data System (ADS)

Pavia, S.; Caro, S.

2007-07-01

Polarised-light (or petrographic) microscopy has been widely applied to heritage materials to assess composition and diagnose damage. However, instead, this paper focuses on the petrographic investigation of brick and mortar technologies for the production of quality repair materials compatible with their adjacent fabrics. Furthermore, the paper relates production technologies to the physical properties of the materials fabricated, and thus their final quality and durability. According to Cesare Brandi´s theory of compatibility (the 20th century architect on whose work modern conservation theory and practice are largely based) existing historic materials should be replaced with their equivalent. This paper demonstrates that polarised-light microscopy provides data on the origin and nature of raw materials, and processing parameters such as blending, mixing, firing, calcination and slaking, and how these relate to the quality of the final product. In addition, this paper highlights the importance of production technologies as these directly impact the physical properties of the materials fabricated and thus determine their final quality and durability. In this context, the paper investigates mortar calcination and slaking, two important operations in the manufacture of building limes that govern the reactivity, shrinkage and water retention of a lime binder which will impact mortar's properties such as workability, plasticity and carbonation speed, and these in turn will determine the ease of execution, durability and strength of a lime mortar. Petrographic analysis also provides evidence of ceramic technology including identification of local or foreign production and processing parameters such as sieving, blending, mixing and firing. A petrographic study of the ceramic matrix coupled to the diagnosis of mineral phases formed during firing allows to quantify sintering and vitrification and thus determine firing temperatures. Finally, certain features of the raw clay such as the grading and the amount and nature of the non-plastic material inform, not only on the raw material's origin, but also impact the physical properties of the ceramic ware.

Interstitial Water Geochemistry and Low Temperature Alteration in Volcaniclastic Sediments from the Amami Sankaku Basin at IODP Site U1438 (Expedition 351)

NASA Astrophysics Data System (ADS)

Loudin, L. C.; Yogodzinski, G. M.; Sena, C.; van der Land, C.; Zhang, Z.; Marsaglia, K. M.; Meffre, S.

2014-12-01

Interstitial water (IW) geochemistry provides insight into the diagenetic transformation of sediment to rock by component dissolution/alteration and precipitation of new mineral phases as pore-filling cements, as well as providing insight into ion exchange reactions with secondary minerals. At Site U1438, 67 IW samples were collected within a ~950 m section of volcaniclastic sediments. These were analyzed for pH as well as major and trace elements. The corresponding host sediments were mineralogically characterized by XRD and petrographic observations. Three alteration zones are inferred: 1) the upper alteration zone (~0-300 mbsf) characterized by maximum IW concentrations of Si (790.1 μM), Sr (138.5 μM) and Mn (279.5 μM), consistent with volcanic glass and siliceous microfossil dissolution, enhanced reduction of Mn oxides, and carbonate recrystallization. Maximum concentrations in Li and B coupled with the lowest pH (6.7) imply that Li and B are released into the IW due to silicate dissolution and clay desorption. 2) At intermediate depths (~300 to ~550 mbsf) Mg, K, Sr, Si, Mn, Li, and B are at concentration minima, possibly due to growth of authigenic minerals. B and Li minimum concentrations occur at high pH (~9) suggesting that these elements are preferentially removed from high pH waters during the precipitation of clay mineral and zeolite cements in primary and secondary (dissolution) pores. The mineralogy of these phases is confirmed by XRD data, and their pore-filling nature is seen in thin sections of the coarser lithologies. 3) The deep alteration zone (>~550m) is characterized by an increase in B, Li, Sr and Ca. At ~650 mbsf, Ca becomes the dominant cation in solution consistent with either mineral interaction with the IW, or diffusive input from underlying igneous basement (~1400 mbsf).

Semi-thin sections of epoxy resin-embedded mouse embryos in morphological analysis of whole mount in situ RNA hybridization.

PubMed

Mitrecić, D; Cunko, V F; Gajović, S

2008-12-01

Descriptive morphological studies are often combined with gene expression pattern analyses. Unembedded vibratome or cryotome sections are compatible with in situ RNA hybridization, but spatial resolution is rather low for precise microscopic studies necessary in embryology. Therefore, use of plastic embedding media, which allow semi-thin and ultra-thin sectioning for light and electron microscopy, could be an important advantage. This work suggested a new approach based on the whole mount hybridization of mouse embryos and subsequent epoxy resin embedding. Epoxy resin allowed serial sectioning of semi-thin sections with preserved in situ RNA hybridization signal, which was a necessary prerequisite for precise morphological analysis of embryo development.

Petrographic Analysis of Cores from Plant 42

DTIC Science & Technology

2016-10-01

ER D C TR -X X- D R AF T Petrographic Analysis of Cores from Plant 42 E n gi n ee r R es ea rc h a n d D ev el op m en t C en te r...E. Rae Reed-Gore, Kyle Klaus, and Robert D. Moser October 2016 Approved for public release; distribution is unlimited. The U.S. Army...ORIGINATOR. ii Figures and Tables Figures Figure 1. Test location map of AF Plant 42 with core number locations. ............................. 2

Geochemical and petrographic data for intrusions peripheral to the Big Timber Stock, Crazy Mountains, Montana

USGS Publications Warehouse

du Bray, Edward A.; Van Gosen, Bradley S.

2015-01-01

The Paleocene Fort Union Formation hosts a compositionally diverse array of Eocene plugs, dikes, and sills arrayed around the Eocene Big Timber stock in the Crazy Mountains of south-central Montana. The geochemistry and petrography of the sills have not previously been characterized or interpreted. The purpose of this report is (1) to present available geochemical and petrographic data for several dozen samples of these rocks and (2) to provide a basic interpretive synthesis of these data.

Paleo-fluid flow in folded, poorly lithified Quaternary sediments revealed by diagenetic concretions developed during the growth of Quattro Castella Anticline (Northern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Pizzati, Mattia; Balsamo, Fabrizio; Iacumin, Paola; Swennen, Rudy; Storti, Fabrizio

2017-04-01

Diagenetic concretions and mineral masses may provide a useful tool to better understand paleo-fluid flows in transforming porous media. Moreover, the selective cementation responsible of diagenetic alterations formation, plays a key role in diminishing sediments porosity and permeability and hence reservoir quality. In compressive settings of a fold-and-thrust-belt, the presence of deep or blind thrusts could lead to the generation of folds which may influence syn-kinematic sedimentation, deep fluids migration and shallow fluid flow pattern. In this contribution we present a multidisciplinary field and laboratory study on carbonate concretions developed in Quaternary poorly lithified, shallow marine syn-kinematic sediments of the Quattro Castella Anticline in Northern Apennines (Italy). The study site is located along the Enza River, where shallow marine to continental sediments are exposed along the forelimb of the fold nucleated during Late Miocene and still active today. Field mapping was aimed to link bedding attitude of syn-kinematic sediments with the geometry, arrangement, shape and size of concretionary bodies. The studied concretions are both tabular (i.e. parallel to sediment bedding) and elongate single or coalescent concretionary bodies (i.e. plunging at different angle to bedding dip throughout the stratigraphic section). Concretions dimensions range from a few centimeters in single elongate concretions, up to a few meters in tabular and coalescent ones. In situ permeability measurements and laboratory grain size analyses were performed along the studied section to constrain the petrophysical properties of sediments hosting carbonate concretions. Carbon and oxygen stable isotopes analyses on carbonate concretions (performed both on hand specimens and also on thin sections), together with petrographic and cathodoluminescence observations, were used to better constrain the diagenetic environment in which calcite precipitation occurred. Our results indicate that the growing anticline promoted the development of a local topographic and hydraulic gradient which induced cement precipitation in the form of carbonate concretions in syn-kinematic sediments. Such diagenetic alterations can be a good marker to reconstruct the paleo-fluid flow history in structurally complex siliciclastic reservoirs.

Petrology of forearc basalt-related isotropic gabbros from the Bonin Ridge, Izu-Bonin forearc

NASA Astrophysics Data System (ADS)

Garcia, S. E.; Loocke, M. P.; Snow, J. E.

2017-12-01

The early arc volcanic rocks exposed on the Bonin Ridge (BR), a large forearc massif in the Izu-Bonin arc, have provided us with a natural laboratory for the study of subduction initiation and early arc development. The BR has been the subject of focused sampling by way of dredging, diving, and drilling (IODP EXP352) expeditions which have revealed a composite stratigraphy consisting, from bottom to top, of intercalated peridotites and gabbros, isotropic gabbros, sheeted dykes, and a lava sequence which transitions from forearc basalt (FAB) to more arc-like volcanics up section. Although little has been published regarding the moho-transition zone rocks of the BR in comparison to the volcanic rocks, even less work has been published regarding the isotropic gabbros recovered in close association with FABs. Ishizuka et al. (2011) determined that the isotropic gabbros are compositionally and temporally related to the FABs. We provide the first petrologic characterization, including petrography and electron probe microanalysis, of a suite of FAB-related gabbros recovered by dredge D42 of the 2007 R/V Hakuho Maru KH07-02 dredging cruise. Preliminary petrographic observations of the fourteen thin sections reveal that all of the samples contain variable amounts of relict orthopyroxene and consist of five disseminated oxide gabbros, 5 oxide gabbros, and 2 gabbros. We note that all of the D42 gabbros exhibit strong textural variability akin to the varitextured gabbros described in the dyke-gabbro transition of ophiolites (e.g., MacLeod and Yaouancq, 2000). Geochemical data from this critically understudied horizon have the potential to inform regarding the nature of crustal accretion during subduction initiation and the formation, migration, and evolution of FABs. Further, with many authors comparing the volcanic record and crustal stratigraphy of the BR to ophiolites (e.g., Ishizuka et al., 2014), these data would provide another in situ analogue for comparison with the gabbroic sections of ophiolites. MacLeod, C.J., Yaouancq, G., 2000, Earth and Planetary Science Letters, 176:357-373. Ishizuka, O., et al., 2011, Earth and Planetary Science Letters, 306: 229-240. Ishizuka, O., Tani, K., Reagan, M.K., 2014, Elements, 10:115-120.

An in vitro method for rapid regeneration of a monopodial orchid hybrid Aranda Deborah using thin section culture.

PubMed

Lakshmanan, P; Loh, C S; Goh, C J

1995-05-01

A thin section culture system for rapid regeneration of the monopodial orchid hybrid Aranda Deborah has been developed. Thin sections (0.6-0.7mm thick) obtained by transverse sectioning of a single shoot tip (6-7mm), when cultured in Vacin and Went medium enriched with coconut water (20% v/v), produced an average 13.6 protocorm-like bodies (PLB) after 45 days, compared to 2.7 PLB formed by a single 6-7 mm long shoot tip under same culture condition. Addition of α-naphthaleneacetic acid to Vacin and Went medium enriched with coconut water further increased PLB production by thin sections. PLB developed into plantlets on solid Vacin and Went medium containing 10% (v/v) coconut water and 0.5 g l(-1) activated charcoal. With this procedure, more than 80,000 plantlets could be produced from thin sections obtained from a single shoot tip in a year as compared to nearly 11,000 plantlets produced by the conventional shoot tip method.

Spectroscopic, microchemical and petrographic analyses of plasters from ancient buildings in Lamezia Terme (Calabria, Southern Italy)

NASA Astrophysics Data System (ADS)

De Luca, Raffaella; Gigliotti, Valentina; Panarello, Mario; Bloise, Andrea; Crisci, Gino M.; Miriello, Domenico

2016-01-01

This work shows the results of the spectroscopic, microchemical and petrographic study carried out on six plasters coming from three important residential buildings of the 18th century, located in Lamezia Terme (Catanzaro, Southern Italy). To study the provenance of the raw materials used to make the plasters, one sample of limestone and two samples of sand were also collected from the quarries near Lamezia Terme and compared with the historical plasters. Samples were studied by polarized optical microscopy (OM), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. The results of these analyses allowed to determine the mineralogical, petrographical and chemical characteristics of the plasters, identify the pigments used for their coloration and provide useful information about the building techniques, the raw materials employed and the production technology of plasters during the 18th century in Lamezia Terme. SEM-EDS microanalysis also revealed the presence of gold and silver on the surface of two samples.

Space Weathering in the Fine Size Fractions of Lunar Soils: Soil Maturity Effects

NASA Technical Reports Server (NTRS)

Keller, L. P.; Wentworth, S. J.; McKay, D. S.; Taylor, L. A.; Pieters, C.; Morris, R. V.

1999-01-01

The effects of space weathering on the optical properties of lunar materials have been well documented. These effects include a reddened continuum slope, lowered albedo, and attenuated absorption features in reflectance spectra of lunar soils as compared to finely comminuted rocks from the same Apollo sites. However, the regolith processes that cause these effects are not well known, nor is the petrographic setting of the products of these processes fully understood. A Lunar Soil Characterization Consortium has been formed with the purpose of systematically integrating chemical and mineralogical data with the optical properties of lunar soils. Understanding space-weathering effects is critical in order to fully integrate the lunar sample collection with remotely-sensed data from recent robotic missions (e.g., Lunar Prospector, Clementine, and Galileo) We have shown that depositional processes (condensation of impact-derived vapors, sputter deposits, accreted impact material, e.g., splash glass, spherules, etc.) are a major factor in the modification of the optical surfaces of lunar regolith materials. In mature soils, it is the size and distribution of the nanophase metal in the soil grains that has the major effect on optical properties. In this report, we compare and contrast the space-weathering effects in an immature and a mature soil with similar elemental compositions. For this study, we analyzed <10 micron sieve fractions of two Apollo 17 soils, 79221 (mature, Is/FeO = 81) and 71061 (immature, Is/FeO = 14). Details of the sieving procedures and allocation scheme are given else where. The results of other detailed chemical, mineralogical, and spectroscopic analyses of these soil samples are reported elsewhere. A representative sample of each soil was embedded in low-viscosity epoxy, and thin sections (about 70nm thick) were obtained through ultra microtomy. The thin sections used for these analyses typically contained cross sections of up to 500 individual grains. The thin sections were studied using a JEOL 2010 transmission electron microscope (TEM) equipped with a thin window energy-dispersive X-ray (EDX) spectrometer. An individual thin section was selected from each soil, and for each grain in the section we determined (1) the elemental composition by EDX; (2) whether the grain was crystalline or glassy using electron diffraction and darkfield imaging; (3) the presence or absence of rims and accreted material; and (4) the distribution of nanophase Fe where present. Most of the categories are self-evident; however, we divide the agglutinate derived material into agglutinitic glass (glass with approximately the same composition as the bulk soil that contains nanophase Fe with or without vesicles) and agglutinate fragments, which are composed of crystalline grains and agglutinitic glass. Lithic fragments are defined as polymineralic grains with no glass. Pyroxene grains have been divided into high- and low-Ca groups. As expected, there are a number of differences in the petrography of the <10-microns fractions of 79221 and 71061 given the great difference in their respective maturities, but we focus here on two major distinctions: agglutinate content and the number of grains with micropatina. Slightly over 50% of the particles in 79221 consist of agglutinitic glass and agglutinate fragments, while the remainder are predominantly crystalline mineral grains. The agglutinic glass particles contain abundant nanophase Fe and vesicles. Angular particles are rare, with most showing smooth, rounded exteriors, Of the mineral grains analyzed thus far, over 90% of the grains have amorphous rims that contain nanophase Fe (these rims are believed to have formed by vapor deposition and irradiation effects). The nanophase Fe in these rims probably accounts for a significant fraction of the increase in Is/FeO measured in these size fractions. In addition to the rims, the majority of particles also show abundant accreted material in the form of glass splashes and spherules that also contain nanophase Fe. In stark contrast, the surfaces of the mineral grains in the 71061 sample are relatively prisitine, as only about 14% of the mineral grains in the sample exhibited amorphous rims. Furthermore, the mineral particles are more angular and show greater surface roughness than in the mature sample. Accreted material on particle surfaces is rare. Agglutinitic material is a major component of the 71061 sample; however, nanophase Fe and vesicles are not as well developed as in the 79221 sample. It is now recognized that nanophase Fe is probably the main agent in modifying the optical properties of lunar soil grains. The most important result of this study is the observation that in the fine size fractions of mature soils, nearly every grain has nanophase Fe within 100 run of the particle surface. (Additional Information contained in original)

Bronze Age pottery from the Aeolian Islands: definition of Temper Compositional Reference Units by an integrated mineralogical and microchemical approach

NASA Astrophysics Data System (ADS)

Brunelli, D.; Levi, S. T.; Fragnoli, P.; Renzulli, A.; Santi, P.; Paganelli, E.; Martinelli, M. C.

2013-12-01

An integrated microchemical-petrographic approach is here proposed to discriminate the provenance of archaeological pottery artefacts from distinct production centres. Our study focuses on a statistically significant sampling ( n=186) of volcanic temper-bearing potteries representative of the manufacturing and dispersion among the islands of the Aeolian Archipelago during the Bronze Age. The widespread establishment of new settlements and the abundant recovery of Aeolian-made ceramic in southern Italy attest for the increased vitality of the Archipelago during the Capo Graziano culture (Early Bronze Age-Middle Bronze Age 2; 2300-1430 BC). Potteries from three of the main known ancient communities (Lipari, Filicudi and Stromboli) have been studied integrating old collections and newly excavated material. Volcanic tempers have been first investigated through multivariate analyses of relative abundances of mineral and rock clasts along with petrographic characters. In addition, we performed in-situ mineral chemistry microanalyses by Electron Microprobe and Laser Ablation—Inductively Coupled Plasma Mass Spectrometry to assess major and trace element composition of the most common mineral phases. Four Temper Compositional Reference Units have been recognised based on compositional trends. Two units (AI and AX) are unequivocally distinct by their peculiar trace element enrichment and petrographic composition; they mostly contain samples from the sites of Lipari and Stromboli, respectively. Units AIV and AVIII, restricted to the sites of Filicudi and Stromboli, show distinct petrographic characters but overlapped geochemical fingerprints.

A comparative analysis of microscopic alterations in modern and ancient undecalcified and decalcified dry bones.

PubMed

Caruso, Valentina; Cummaudo, Marco; Maderna, Emanuela; Cappella, Annalisa; Caudullo, Giorgio; Scarpulla, Valentina; Cattaneo, Cristina

2018-02-01

The present study aims to evaluate the preservation of the microstructure of skeletal remains collected from four different known burial sites (archaeological and contemporary). Histological analysis on undecalcified and decalcified thin sections was performed in order to assess which of the two techniques is more affected by taphonomic insults. A histological analysis was performed on both undecalcified and decalcified thin sections of 40 long bones and the degree of diagenetic change was evaluated using transmitted and polarized light microscopy according to the Oxford Histological Index (OHI). In order to test the optical behavior of bone tissue, thin sections were observed by polarized light microscopy and the intensity of birefringence was evaluated. The more ancient samples are generally characterized by a low OHI (0-1) with extensive microscopic focal destruction; recent samples exhibited a better preservation of bone micromorphology. When comparing undecalcified to decalcified thin sections, the latter showed an amelioration in the conservation of microscopic structure. As regards the birefringence, it was very low in all the undecalcified thin sections, whereas decalcification process seems to improve its visibility. The preservation of the bone microscopic structure appears to be influenced not only by age, but also by the burial context. Undecalcified bones appear to be more affected by taphonomical alterations, probably because of the thickness of the thin sections; on the contrary, decalcified thin sections proved to be able to tackle this issue allowing a better reading of the bone tissue. © 2017 Wiley Periodicals, Inc.

Observations on the palynology, petrography and geochemistry of the Western Kentucky number 4 coal bed

USGS Publications Warehouse

Eble, C.F.; Greb, S.F.; Williams, D.A.; Hower, J.C.

1999-01-01

Eight bench-column samples of the Western Kentucky Number 4 coal bed, collected from an area along the southern margin of the Western Kentucky Coal Field, were analyzed palynologically, petrographically, and geochemically to document both temporal and spatial variability among these parameters. The Western Kentucky Number 4 coal occurs near the top of the Tradewater Formation, is of Early Desmoinesian age, and is correlative with the lower part of the Allegheny Formation of the Appalachian Basin, and Late Bolsovian strata of western Europe. Palynologically, the coal is co-dominated by spores that were produced by lycopod trees (Lycospora and Granasporites medius) and tree ferns. Thin-walled tree fern spores (Punctatisporites minutus, P. minutus, P. rotundus) are more abundant than thick-walled forms (Laevigatosporites globosus, P. granifer). Calamitean spores (Calamospora and Laevigatosporites spp.) are locally abundant as is cordaitean pollen (Florinites). Small fern (Granulatisporites) and small lycopod spores (Densosporites, Cirratriradites, Endosporites and Anacanthotriletes spinosus) are present, but occur in minor amounts. Temporal changes in palynomorph composition occur, but are not uniform between columns. Spatial variability among columns is also evident. Petrographically, the coal is dominated by vitrinite macerals, with telinite and telocollinite generally occurring more commonly than desmocollinite and gelocollinite. Basal benches typically contain high percentages of vitrinite; middle benches usually contain higher percentages of liptinite and inertinite. In about half the studied columns, the terminal coal benches show a slight increase in vitrinite. In the study area, the petrography of the Western Kentucky Number 4 coal is more uniform than the palynology. Ash yields and total sulfur contents are temporally uniform in some columns, but variable in others. In the latter case, higher percentages of ash and sulfur occur at the base of the bed and decrease up to the middle of the bed. The terminal benches of these columns often, but not always, show slight increases in ash or sulfur. Both syngenetic and epigenetic forms of sulfur are present in the Western Kentucky Number 4 coal. The high vitrinite contents and moderate to high sulfur contents suggest that the Western Kentucky Number 4 paleomire was mainly planar and rheotrophic throughout its developmental history. Groundwaters carrying dissolved solutes may have helped neutralize the normally acidic interstitial peat waters allowing for the production of sulfide minerals. Several of the columns with high sulfur contents at the base of the bed occur in faulted areas. The faults could have promoted the flow of groundwaters through the peat, providing an increased dissolved load for acid mitigation and sulfide formation. The concentration of sulfur at the base of the bed may be a function of the peat/underclay contact enhancing sulfide formation. The clay layer may also have acted as an impermeable boundary for downward moving groundwaters, causing mainly lateral, rather than vertical movement along the base of the coal bed.Eight bench-column samples of the Western Kentucky Number 4 coal bed were analyzed palynologically, petrographically, and geochemically to study both temporal and spatial variability among these parameters. Palynologically, the coal is co-dominated by spores that were produced by lycopod trees and tree ferns. Petrographically, the coal is dominated by vitrinite macerals, with telinite and telocollinite generally occurring more commonly than desmocollinite and gelocollinite. The petrography of the coal was found to be more uniform than the palynology.

Cement line staining in undecalcified thin sections of cortical bone

NASA Technical Reports Server (NTRS)

Bain, S. D.; Impeduglia, T. M.; Rubin, C. T.

1990-01-01

A technique for demonstrating cement lines in thin, undecalcified, transverse sections of cortical bone has been developed. Cortical bone samples are processed and embedded undecalcified in methyl methacrylate plastic. After sectioning at 3-5 microns, cross-sections are transferred to a glass slide and flattened for 10 min. Sections of cortical bone are stained for 20 sec free-floating in a fresh solution of 1% toluidine blue dissolved in 0.1% formic acid. The section is dehydrated in t-butyl alcohol, cleared in xylene, and mounted with Eukitt's medium. Reversal lines appear as thin, scalloped, dark blue lines against a light blue matrix, whereas bone formation arrest lines are thicker with a smooth contour. With this technique cellular detail, osteoid differentiation, and fluorochrome labels are retained. Results demonstrate the applicability of a one-step staining method for cement lines which will facilitate the assessment of bone remodeling activity in thin sections of undecalcified cortical bone.

3-D X-ray tomography of diamondiferous mantle eclogite xenoliths, Siberia: A review

NASA Astrophysics Data System (ADS)

Howarth, Geoffrey H.; Sobolev, Nikolay V.; Pernet-Fisher, John F.; Ketcham, Richard A.; Maisano, Jessica A.; Pokhilenko, Lyudmila N.; Taylor, Dawn; Taylor, Lawrence A.

2015-04-01

Diamonds form over billions of years, hundreds of kilometers beneath the Earth's surface, and in combination with inclusions trapped within, provide important constraints on the evolution of the mantle over geological time. Diamonds are generally studied as individual crystals sourced from highly explosive kimberlite pipes, which entrain and subsequently disaggregate mantle fragments (xenoliths) en route to the surface. This has resulted in a general absence of robust textural descriptions of diamonds relative to their hosting mantle protolith. The textural associations of diamonds within their mantle host rocks are reviewed here on the basis of a compilation of X-ray tomographic data for 17 diamondiferous eclogite xenoliths from Siberian kimberlites. This review represents a comprehensive description of diamonds relative to their host silicates. The lack of such descriptions in previous studies is largely due to the rarity of these xenoliths, the difficulty in preparing petrographic thin sections containing diamonds, and their high-monetary value. High-resolution computed X-ray tomography (HRCXT) produces up to 1200 sequential 2-D slices through individual xenoliths, each of which represents a 'pseudo thin-section' with a resolution on the order of 5-20 μm. The improved resolution of X-ray imaging in recent studies allows for the identification of not only primary minerals, but metasomatic minerals assemblages, including: 'spongy' textured clinopyroxene, phlogopite/K-richterite, and hercynitic spinel, allowing for the delineation of distinct metasomatic pathways through the xenoliths and their relationship to diamonds. Diamonds are observed in three distinct textural settings, potentially representing several temporally distinct diamond growth events, these setting includes: (1) diamonds completely enclosed in garnet; (2) diamonds associated with highly embayed silicate grain boundaries; and (3) diamonds contained within distinct metasomatic 'plumbing-systems'. Diamonds observed completely enclosed in garnets suggest an early diamond-forming event prior to major re-crystallization and eclogite formation during subduction. The occurrence of diamond in association with embayed garnets suggests that diamond grew at the expense of the hosting silicate protolith. In addition, the spatial relationships of diamonds with metasomatic pathways, which are generally interpreted to result from late-stage proto-kimberlitic fluid percolation, indicate a period of diamond growth occurring close to, but prior to, the time of kimberlite emplacement. Furthermore, the paragenesis of sulfides within eclogite xenoliths are described using 3-D models for entire xenoliths volumes, providing important constraints of the timing of sulfide mobilization within the mantle. Three-D animations created using X-ray tomography data for ten of the xenoliths can be viewed at the following link: http://eps.utk.edu/faculty/taylor/tomography.php

An integrated approach to reservoir modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donaldson, K.

1993-08-01

The purpose of this research is to evaluate the usefulness of the following procedural and analytical methods in investigating the heterogeneity of the oil reserve for the Mississipian Big Injun Sandstone of the Granny Creek field, Clay and Roane counties, West Virginia: (1) relational database, (2) two-dimensional cross sections, (3) true three-dimensional modeling, (4) geohistory analysis, (5) a rule-based expert system, and (6) geographical information systems. The large data set could not be effectively integrated and interpreted without this approach. A relational database was designed to fully integrate three- and four-dimensional data. The database provides an effective means for maintainingmore » and manipulating the data. A two-dimensional cross section program was designed to correlate stratigraphy, depositional environments, porosity, permeability, and petrographic data. This flexible design allows for additional four-dimensional data. Dynamic Graphics[sup [trademark

Sandstone petrographic evidence and the Chugach-Prince William terrane boundary in southern Alaska

USGS Publications Warehouse

Dumoulin, Julie A.

1988-01-01

The contact between the Upper Cretaceous Valdez Group and the Paleocene and Eocene Orca Group has been inferred to be the boundary between the Chugach and the Prince William tectonostratigraphic terranes. Sandstone petrographic data from the Prince William Sound area show no compositional discontinuity across this contact. These data are best explained by considering the Valdez and Orca Groups to be part of a single terrane - a thick flysch sequence derived primarily from a progressively unroofing magmatic arc with increasing input from subduction-complex sources through time.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutcu, H.; Toroglu, I.; Piskin, S.

Turkey, especially Zonguldak on the West Coast of Black Sea region, has large reserves of bituminous coal that can be used either directly or in blends with other coals for metallurgical coke production. It is possible to predict the coking properties of these coals by petrographic analysis. In this study, semi- and non-coking coals were blended with coking bituminous coals in varying proportions and an estimation was made as to their stability factors through petrographic techniques. It was established that semi- and non-coking bituminous coals could be used in the production of metallurgical coke.

GEMS and New Pre-Accretionally Irradiated RELICT Grains in Interplanetary Dust - The Plot Thickens

NASA Astrophysics Data System (ADS)

Bradley, J.

1995-09-01

The hypothesis that GEMS (glass with embedded metal and sulfides) in interplanetary dust particles (IDPs) might be the long-sought interstellar silicate grains is undergoing close scrutiny [1-3]. GEMS are proposed to be interstellar because: (a) they are abundant in cometary IDPs; (b) they were irradiated prior to incorporation into IDPs; (c) both their size distribution and Oamorphous silicate" microstructures are consistent with those of interstellar silicates; (d) they contain nanometer-sized (superparamagnetic) alpha-iron inclusions, which provides a simple explanation for the observed interstellar grain alignment and polarization [4,5]. Challenges to the GEMS hypothesis include the following: (a) GEMS may have formed and been irradiated in the solar nebula rather than a presolar interstellar environment; (b) non-solar isotope abundances have yet to be measured in GEMS; (c) the irradiation regime required to produce the observed effects in GEMS might be incompatible with the interstellar medium; (b) relationships between GEMS and carbon (e.g. core/mantle) need clarification; (c) major element abundances in GEMS should be consistent with observed interstellar gas phase depletions [2,3]. GEMS may indeed have formed in the solar nebula, in which case they would be the oldest known solar nebula solids [2]. An interstellar origin for GEMS does not require detection of non-solar isotope abundances [6]. Irradiation experiments are in progress to simulate the properties of GEMS. The petrographic relationship between GEMS and carbon in IDPs is being investigated (by examining IDPs embedded and thin-sectioned in carbon-free media). Major element abundances in GEMS are being evaluated in terms on interstellar gas phase abundances. For example, sulfur is not highly depleted in the interstellar gas, implying that it must be significantly depleted in interstellar grains [3]. GEMS are significantly depleted in sulfur relative to solar abundances. Analytical electron microscopic studies of the local petrographic environment of GEMS in IDPs are continuing. There is evidence of a population of relict grains associated with GEMS. Some of these relict grains have distinctive compositions and they appear to have functioned as (pre-existing) depositional substrates while GEMS were being formed. Thus, it may be possible to begin to assign a chronology to the seemingly complex admixture of grains that make up the ultrafine-grained matrices of anhydrous chondritic IDPs. References: [1] Bradley J. P. (1994) Science, 265, 925-929. [2] Flynn G. J. (1994) Nature, 371, 287-288. [3] Martin P. G. (1995) Astrophys. J., 445, L63-L66. [4] Mathis J. S. (1986) Astrophys. J., 308, 281-287. [5] Mathis J. S. (1993) Rept. Prog. Phys., 56, 605-652. [6] Walker R. M. (1994) in Analysis of Interplanetary Dust (M. E. Zolensky et al., eds.), pp. 203-209, AIP Conf. Proc. 310.

Studying the impact of air/brine displacement on acoustic velocities in carbonates. El Amin Mokhtar and Sandra Vega

NASA Astrophysics Data System (ADS)

Mokhtar, E.; Vega, D.

2012-12-01

The impact of air/brine displacement on acoustic velocities of carbonate rocks is not fully comprehended yet. In order to improve our understanding of this effect, we conducted laboratory measurements of porosity and acoustic velocities (Vp and Vs) under both dry and brine saturated conditions at ambient pressure and temperature. The core plug samples in this study were collected from a hydrocarbon reservoir in the Middle East. A petrographic analysis was also performed on thin sections taken from the core plugs using a microscope and a digital camera. The aim of this analysis was to study depositional facies and the extent of diagenetic overprint that caused the observed variations in rock fabrics. Cross-plots were generated to analyze the trends of behavior between acoustic velocities and porosities taking into account the influence of different rock fabrics, in both dry and brine saturated samples. Acoustic velocities of brine saturated samples were higher than velocities of dry samples, as expected. However, their differences also respond to both, total porosity and carbonate rock fabrics. This result can be attributed to the different carbonate pore structures and rock frames formed during deposition and diagenesis. Similarly, the Vp/Vs ratio cross-plots display an increase in Vp/Vs ratios for the brine saturated samples compared to the dry ones. In conclusion, differences in acoustic velocities between dry and brine saturated carbonate rocks seem to be highly effected by porosity, rock fabric, and fluid content. This information can help to better understand the differences in acoustic response between gas and brine saturated zones in well logs and seismic.

The benefit of a tough skin: bullet holes, weathering and the preservation of heritage

PubMed Central

Gomez-Heras, M.; Brassey, C.; Green, O.; Blenkinsop, T.

2017-01-01

Projectile damage to building stone is a widespread phenomenon. Sites damaged 100 years ago during the First World War still see daily use, while in a more contemporary setting numerous reports show the damage to buildings in Babylon, Mosul and Palmyra. While research has been carried out on the long-term effects of conflict such as fire damage, little is known about the protracted damage sustained through the impact of bullets, shrapnel and other metal projectiles outside of the field of engineering focused on ceramics and metals. To investigate alterations to mineral structure caused by projectile damage, impacts were created in medium-grained, well-compacted, mesoporous sandstone samples using 0.22 calibre lead bullets shot at a distance of 20 m. Half these samples were treated with a surface consolidant (Wacker OH 100), to mimic natural cementation of the rock surface. These samples were then tested for changes to surface hardness and moisture movement during temperature cycles of 15–65°C. Petrographic thin section analysis was carried out to investigate the micro-scale deformation associated with high-speed impact. The results surprisingly show that stress build-up behind pre-existing cementation of the surface, as found in heritage sites that have been exposed to moisture and temperature fluctuations for longer periods of time, can be alleviated with a bullet impact. However, fracture networks and alteration of the mineral matrices still form a weak point within the structure, even at a relatively low impact calibre. This initial study illustrates the need for geomorphologists, geologists, engineers and heritage specialists to work collectively to gain further insights into the long-term impact of higher calibre armed warfare on heritage deterioration. PMID:28386411

The benefit of a tough skin: bullet holes, weathering and the preservation of heritage

NASA Astrophysics Data System (ADS)

Mol, Lisa; Gomez-Heras, M.; Brassey, C.; Green, O.; Blenkinsop, T.

2017-02-01

Projectile damage to building stone is a widespread phenomenon. Sites damaged 100 years ago during the First World War still see daily use, while in a more contemporary setting numerous reports show the damage to buildings in Babylon, Mosul and Palmyra. While research has been carried out on the long-term effects of conflict such as fire damage, little is known about the protracted damage sustained through the impact of bullets, shrapnel and other metal projectiles outside of the field of engineering focused on ceramics and metals. To investigate alterations to mineral structure caused by projectile damage, impacts were created in medium-grained, well-compacted, mesoporous sandstone samples using 0.22 calibre lead bullets shot at a distance of 20 m. Half these samples were treated with a surface consolidant (Wacker OH 100), to mimic natural cementation of the rock surface. These samples were then tested for changes to surface hardness and moisture movement during temperature cycles of 15-65°C. Petrographic thin section analysis was carried out to investigate the micro-scale deformation associated with high-speed impact. The results surprisingly show that stress build-up behind pre-existing cementation of the surface, as found in heritage sites that have been exposed to moisture and temperature fluctuations for longer periods of time, can be alleviated with a bullet impact. However, fracture networks and alteration of the mineral matrices still form a weak point within the structure, even at a relatively low impact calibre. This initial study illustrates the need for geomorphologists, geologists, engineers and heritage specialists to work collectively to gain further insights into the long-term impact of higher calibre armed warfare on heritage deterioration.

Volcanic ash in ancient Maya ceramics of the limestone lowlands: implications for prehistoric volcanic activity in the Guatemala highlands

NASA Astrophysics Data System (ADS)

Ford, Anabel; Rose, William I.

1995-07-01

In the spirit of collaborative research, Glicken and Ford embarked on the problem of identifying the source of volcanic ash used as temper in prehistoric Maya ceramics. Verification of the presence of glass shards and associated volcanic mineralogy in thin sections of Maya ceramics was straightforward and pointed to the Guatemala Highland volcanic chain. Considering seasonal wind rose patterns, target volcanoes include those from the area west of and including Guatemala City. Joint field research conducted in 1983 by Glicken and Ford in the limestone lowlands of Belize and neighboring Guatemala, 300 km north of the volcanic zone and 150 km from the nearest identified ash deposits, was unsuccessful in discovering local volcanic ash deposits. The abundance of the ash in common Maya ceramic vessels coupled with the difficulties of long-distance procurement without draft animals lead Glicken to suggest that ashfall into the lowlands would most parsimoniously explain prehistoric procurement; it literally dropped into their hands. A major archaeological problem with this explanation is that the use of volcanic ash occurring over several centuries of the Late Classic Period (ca. 600-900 AD). To accept the ashfall hypothesis for ancient Maya volcanic ash procurement, one would have to demonstrate a long span of consistent volcanic activity in the Guatemala Highlands for the last half of the first millennium AD. Should this be documented through careful petrographic, microprobe and tephrachronological studies, a number of related archaeological phenomena would be explained. In addition, the proposed model of volcanic activity has implications for understanding volcanism and potential volcanic hazards in Central America over a significantly longer time span than the historic period. These avenues are explored and a call for further collaborative research of this interdisciplinary problem is extended in this paper.

On the Basic Principles of Igneous Petrology

NASA Astrophysics Data System (ADS)

Marsh, B. D.

2014-12-01

How and why Differentiation occurs has dominated Igneous Petrology since its beginning (~1880) even though many of the problems associated with it have been thoroughly solved. Rediscovery of the proverbial wheel with new techniques impedes progress. As soon as thin section petrography was combined with rock and mineral chemistry, rock diversity, compositional suites, and petrographic provinces all became obvious. The masterful 1902 CIPW norm in a real sense solved the chemical mystery of differentiation: rocks are related by the addition and subtraction of minerals in the anciently appreciated process of fractional crystallization. Yet few believed this, even after phase equilibria arrived. Assimilation, gas transfer, magma mixing, Soret diffusion, immiscibility, and other processes had strong adherents, even though by 1897 Becker conclusively showed the ineffectiveness of molecular diffusion in large-scale processes. The enormity of heat to molecular diffusion (today's Lewis no.) should have been convincing; but few paid attention. Bowen did, and he refined and restated the result; few still paid attention. And in spite of his truly masterful command of experiment and field relations in promoting fractional crystallization, Fenner and others fought him with odd arguments. The beauty of phase equilibria eventually dominated at the expense of knowing the physical side of differentiation. Bowen himself saw and struggled with the connection between physical and chemical processes. Progress has come from new concepts in heat transfer, kinetics, and slurry dynamics. The key approach is understanding the dynamic competition between spatial rates of solidification and all other processes. The lesson is clear: Scholarship and combined field, laboratory and technical expertise are critical to understanding magmatic processes. Magma is a limitlessly enchanting and challenging material wherein physical processes buttressed by chemistry govern.

Quantitative petrographic analysis of Desmoinesian sandstones from Oklahoma

USGS Publications Warehouse

Dyman, Thaddeus S.

1989-01-01

Desmoinesian sandstones from the northern Oklahoma platform and the Anadarko, Arkoma, and Ardmore basins record a complex interaction between mid-Pennsylvanian source-area tectonism and cyclic sedimentation patterns associated with numerous transgressions and regressions. Framework-grain summaries for 50 thin sections from sandstones of the Krebs, Cabaniss, and Marmaton Groups and their surface and subsurface equivalents were subjected to multivariate statistical analyses to establish regional compositional trends for provenance analysis. R-mode cluster and correspondence analyses were used to determine the contributing effect (total variance) of key framework grains. Fragments of monocrystalline and polycrystalline quartz; potassium and plagioclase feldspar; chert; and metamorphic, limestone, and mudstone-sandstone rock fragments contribute most to the variation in the grain population. Q-mode cluster and correspondence analyses were used to identify four petrofacies and establish the range of compositional variation in Desmoinesian sandstones. Petrofacies I is rich in monocrystalline quartz (78-98%); mica and rock fragments are rare. Petrofacies II is also rich in monocrystalline quartz (60-84%) and averages 12% total rock fragments. Petrofacies III and IV are compositionally heterogeneous and contain variable percentages of monocrystalline and polycrystalline quartz, potassium feldspar, mica, chert, and metamorphic and sedimentary rock fragments. Quantitative analyses indicate that Desmoinesian sandstones were derived from sedimentary, igneous, and metamorphic source areas. Sandstones of petrofacies I and II occur mostly in the lower Desmoinesian and are widely distributed, although they are most abundant in eastern and central Oklahoma; sandstones of petrofacies III and IV are widely distributed and occur primarily in the middle and upper Desmoinesian. The range of compositional variation and the distribution of petrofacies are related to paleotectonics and basin development, sediment recycling, and varying depositional environments.

Relative abundances of chondrule primary textural types in ordinary chondrites and their bearing on conditions of chondrule formation

NASA Astrophysics Data System (ADS)

Gooding, J. L.; Keil, K.

1981-03-01

A petrographic survey of > 1600 chondrules in thin-sections of 12 different mildly to highly unequilibrated H-, L-, and Li-chondrites, as well as morphological and textural study of 141 whole chondrules separated from 11 of the same chondrites, was used to determine the relative abundances of definable chondrule primary textural types. Percentage abundances of various chondrule types are remarkably similar in all chondrites studied and are ˜47-52 porphyritic olivine-pyroxene (POP), 15-27 porphyritic olivine (P 0), 9-11 porphyritic pyroxene (PP), 34 barred olivine (BO), 7-9 radial pyroxene (RP), 2-5 granular olivine-pyroxene (GOP), 3-5 cryptocrystalline (C), and ≥ 1 metallic (M). Neither chondrule size nor shape is strongly correlated with textural type. Compound and cratered chondrules, which are interpreted as products of collisions between plastic chondrules, comprise ˜2-28% of non-porphyritic (RP, GOP, C) but only ˜2-9% of porphyritic (POP, PO, PP, BO) chondrules, leading to a model-dependent implication that non-porphyritic chondrules evolved at number densities (chondrules per unit volume of space) which were 102 to 104 times greater than those which prevailed during porphyritic chondrule formation (total range of ˜1 to ˜106 m-3. Distinctive "rims" of fine-grained sulfides and/or silicates occur on both porphyritic and non-porphyritic types and appear to post-date chondrule formation. Apparently, either the same process(es) contributed chondrules to all unequilibrated ordinary chondrites or, if genetically different, the various chondrule types were well mixed before incorporation into chondrites. Melting of pre-existing materials is the mechanism favored for chondrule formation.

Breccia 66055 and related clastic materials from the Descartes region, Apollo 16

NASA Technical Reports Server (NTRS)

Fruchter, J. S.; Kridelbaugh, S. J.; Robyn, M. A.; Goles, G. G.

1974-01-01

Trace and major element contents obtained by instrumental neutron activation are reported for a number of Apollo 16 soil samples and miscellaneous breccia fragments. In addition, data obtained by instrumental neutron activation and electron microprobe techniques along with petrographic descriptions are presented for selected subsamples of breccia 66055. The compositions of our soil samples can be modeled by mixtures of various amounts of anorthosite, anorthositic gabbro and low-K Fra Mauro basalt components. These mixtures are typical of those found in a number of petrographic surveys of the fines. Breccia 66055 is a complex regolith breccia which consists of at least four distinct types of microbreccias. No systematic relation with respect to stratigraphic age among the various microbreccia types was observed. Compositionally and texturally, the clasts which compose breccia 66055 are similar to a number of previously reported rock types from the Apollo 16 area. The entire breccia appears to have undergone a complex history of thermal metamorphism. We conclude from the study of these samples that the Cayley Formation is probably homogeneous in its gross compositional and petrographic aspects.

Morphological and Petrographic Analysis of the Volcanic Products (Ashes, Bombs, and Blocks) from Poás Volcano: April-June 2017 Eruptive Period

NASA Astrophysics Data System (ADS)

Lücke, O. H.; Madrigal Quesada, P.

2017-12-01

During the first semester of 2017, Poas Volcano, in the Central American Volcanic Arc (CAVA) initiated a period of volcanic unrest that included high energy phreatomagmatic to magmatic eruptions. The eruptions that occurred on April 14th and April 22nd of 2017 produced abundant ashes and ballistic materials. Here we present results from the morphological and petrographic analyses conducted in the collected material from the largest eruptions of April 2017. Mineral textures observed on the petrographic analyses show evidence of reactivation and fragmentation of a crystal mush in the magma chamber, triggering re-melting episodes, volatile exsolution, and an increase in the pressure of the system, all of which are expected conditions during an eruption episode. Our analyses done on junvenile and non-juvenile material suggest that processes of magma mingling and injections of new batches of material of different compositions have played an important role throughout previous historical eruptions and likely in the current phase of volcanic activity in Poas.

Apollo-11 lunar sample information catalogue

NASA Technical Reports Server (NTRS)

Kramer, F. E. (Compiler); Twedell, D. B. (Compiler); Walton, W. J. A., Jr. (Compiler)

1977-01-01

The Apollo 11 mission is reviewed with emphasis on the collection of lunar samples, their geologic setting, early processing, and preliminary examination. The experience gained during five subsequent missions was applied to obtain physical-chemical data for each sample using photographic and binocular microscope techniques. Topics discussed include: binocular examination procedure; breccia clast dexrriptuons, thin section examinations procedure typical breccia in thin section, typical basalt in thin section, sample histories, and chemical and age data. An index to photographs is included.

Thin-Section Computed Tomography Manifestations During Convalescence and Long-Term Follow-Up of Patients with Severe Acute Respiratory Syndrome (SARS).

PubMed

Wu, Xiaohua; Dong, Dawei; Ma, Daqing

2016-08-08

BACKGROUND SARS is not only an acute disease, but also leads to long-term impaired lung diffusing capacity in some survivors. However, there is a paucity of data regarding long-term CT findings in survivors after SARS. The aim of this study was to assess the changes in lung function and lung thin-section computed tomography (CT) features in patients recovering from severe acute respiratory syndrome (SARS), especially the dynamic changes in ground-glass opacity (GGO). MATERIAL AND METHODS Clinical and radiological data from 11 patients with SARS were collected. The serial follow-up thin-section CTs were evaluated at 3, 6, and 84 months after SARS presentation. The distribution and predominant thin-section CT findings of lesions were evaluated. RESULTS The extent of the lesions on the CT scans of the 11 patients decreased at 6 and 84 months compared to 3 months. The number of segments involved on 84-month follow-up CTs was less than those at 6 months (P<0.05). The predominant thin-section CT manifestation at 84 months (intralobular and interlobular septal thickening) was different than that at 6 months, at which GGO was predominant. CONCLUSIONS During convalescence after SARS, GGO and intralobular and interlobular septal thickening were the main thin-section CT manifestation. Intralobular and interlobular septal thickening predominated over GGO at 84 months.

Implications of new petrographic analysis for the Olmec "mother culture" model.

PubMed

Flannery, Kent V; Balkansky, Andrew K; Feinman, Gary M; Grove, David C; Marcus, Joyce; Redmond, Elsa M; Reynolds, Robert G; Sharer, Robert J; Spencer, Charles S; Yaeger, Jason

2005-08-09

Petrographic analysis of Formative Mexican ceramics by J. B. Stoltman et al. (see the companion piece in this issue of PNAS) refutes a recent model of Olmec "one-way" trade. In this paper, we address the model's more fundamental problems of sampling bias, anthropological implausibility, and logical non sequiturs. No bridging argument exists to link motifs on pottery to the social, political, and religious institutions of the Olmec. In addition, the model of unreciprocated exchange is implausible, given everything that the anthropological and ethnohistoric records tell us about non-Western societies of that general sociopolitical level.

The petrographic microscope: Evolution of a mineralogical research instrument

USGS Publications Warehouse

Kile, D.E.

2003-01-01

The petrographic microscope, designed to observe and measure the optical properties of minerals as a means of identifying them, has provided a foundation for mineralogical and petrological research for more than 120 years. Much of what is known today in these fields is attributable to this instrument, the development of which paralleled an evolution of fundamental optical theory and its correlation with mineral structure and composition. This instrument and its related accessories have evolved through a range of models and designs, which are in themselves distinctive for their scientific function and elegant construction, and are today prized by collectors of scientific instruments.

Petrography and provenance of Apollo 15 soils

NASA Technical Reports Server (NTRS)

Basu, A.; Mckay, D. S.

1979-01-01

Preliminary petrographic and electron probe data from Apollo 15 soils, collected as a part of a comprehensive project, are presented and four principal soil petrographic provinces at the Apollo 15 site are examined. The ratio of non-mare/mare component decreases gradually from the Apennine Front in the south to the mare surface in the north. KREEP basalts appear to be an essential component of the Apennine Bench Formation. The ANT suite rocks contribute only slightly to the population of monomineralic pyroxene, but approximately 30% of the monomineralic olivine are derived from this suite, suggesting troctolitic and dunitic sources.

Methods for making thin layers of crystalline materials

DOEpatents

Lagally, Max G; Paskiewicz, Deborah M; Tanto, Boy

2013-07-23

Methods for making growth templates for the epitaxial growth of compound semiconductors and other materials are provided. The growth templates are thin layers of single-crystalline materials that are themselves grown epitaxially on a substrate that includes a thin layer of sacrificial material. The thin layer of sacrificial material, which creates a coherent strain in the single-crystalline material as it is grown thereon, includes one or more suspended sections and one or more supported sections.

Novel Thin Film Sensor Technology for Turbine Engine Hot Section Components

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Fralick, Gustave C.

2007-01-01

Degradation and damage that develops over time in hot section components can lead to catastrophic failure of the turbine section of aircraft engines. A range of thin film sensor technology has been demonstrated enabling on-component measurement of multiple parameters either individually or in sensor arrays including temperature, strain, heat flux, and flow. Conductive ceramics are beginning to be investigated as new materials for use as thin film sensors in the hot section, leveraging expertise in thin films and high temperature materials. The current challenges are to develop new sensor and insulation materials capable of withstanding the extreme hot section environment, and to develop techniques for applying sensors onto complex high temperature structures for aging studies of hot propulsion materials. The technology research and development ongoing at NASA Glenn Research Center for applications to future aircraft, launch vehicles, space vehicles, and ground systems is outlined.

Geochemical and mineralogical methods of prospecting for mineral deposits

USGS Publications Warehouse

Fersman, A. Ye; Borovik, S. A.; Gorshkov, G.V.; Popov, S.D.; Sosedko, A.F.; Hartsock, Lydia; Pierce, A.P.

1952-01-01

Fersman's book "Geochemical and mineralogical methods of prospecting for mineral deposits" (Geokhimicheskiye i mineralogicheskiye metody poiskov poleznykh iskopayemykh) covers all petrographic, mineralogical, and geochemical techniques that are used either directly or indirectly in mineral exploration. Chapter IV is of particular interest because it describes certain geochemical methods and principles that have not been widely applied outside of the Soviet Union. The original contained a number of photographs that have been omitted; the titles of the photographs are given in the body of the text. Wherever possible, bibliographic references have been checked, and the full titles given. References given in footnotes in the original have been collected and added at the end of each section as a bibliography.

7 CFR 29.2663 - Thin Leaf (C Group).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Thin Leaf (C Group). 29.2663 Section 29.2663... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2663 Thin Leaf (C Group). This group consists of leaves that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin...

7 CFR 29.2663 - Thin Leaf (C Group).

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Thin Leaf (C Group). 29.2663 Section 29.2663... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2663 Thin Leaf (C Group). This group consists of leaves that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin...

7 CFR 29.2663 - Thin Leaf (C Group).

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Thin Leaf (C Group). 29.2663 Section 29.2663... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2663 Thin Leaf (C Group). This group consists of leaves that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin...

7 CFR 29.2663 - Thin Leaf (C Group).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Thin Leaf (C Group). 29.2663 Section 29.2663... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2663 Thin Leaf (C Group). This group consists of leaves that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin...

7 CFR 29.2663 - Thin Leaf (C Group).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Thin Leaf (C Group). 29.2663 Section 29.2663... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2663 Thin Leaf (C Group). This group consists of leaves that are thin in body. Grades Grade names and specifications C1L Choice Light-brown Thin Leaf. Thin...

Preparation methodologies and nano/microstructural evaluation of metal/semiconductor thin films.

PubMed

Chen, Zhiwen; Jiao, Zheng; Wu, Minghong; Shek, Chan-Hung; Wu, C M Lawrence; Lai, Joseph K L

2012-01-01

Metal/semiconductor thin films are a class of unique materials that are widespread technological applications, particularly in the field of microelectronic devices. Assessment strategies of fractal and tures are of fundamental importance in the development of nano/microdevices. This review presents the preparation methodologies and nano/microstructural evaluation of metal/semiconductor thin films including Au/Ge bilayer films and Pd-Ge alloy thin films, which show in the form of fractals and nanocrystals. Firstly, the extended version of Au/Ge thin films for the fractal crystallization of amorphous Ge and the formation of nanocrystals developed with improved micro- and nanostructured features are described in Section 2. Secondly, the nano/microstructural characteristics of Pd/Ge alloy thin films during annealing have been investigated in detail and described in Section 3. Finally, we will draw the conclusions from the present work as shown in Section 4. It is expected that the preparation methodologies developed and the knowledge of nano/microstructural evolution gained in metal/semiconductor thin films, including Au/Ge bilayer films and Pd-Ge alloy thin films, will provide an important fundamental basis underpinning further interdisciplinary research in these fields such as physics, chemistry, materials science, and nanoscience and nanotechnology, leading to promising exciting opportunities for future technological applications involving these thin films.

Petrographic and geochemical characterization of the granitic rocks of the Araguainha impact crater, Brazil

NASA Astrophysics Data System (ADS)

Silva, Dailto; Lana, Cristiano; Souza Filho, Carlos Roberto

2016-03-01

Petrographic and geochemical data obtained on the Araguainha impact crater (Goiás/Mato Grosso States, Brazil) indicate the existence of several molten products that originated during impact-induced congruent melting of an alkali-granite exposed in the inner part of the central uplift of the structure. Although previous studies have described these melts to some extent, there is no detailed discussion on the petrographic and geochemical variability in the granite and its impactogenic derivatives, and therefore, little is known about the geochemical behavior and mobility of trace elements during its fusion in the central part of the Araguainha crater. This paper demonstrates that the preserved granitoid exposed in the core of the structure is a magnesium-rich granite, similar to postcollisional, A-type granites, also found in terrains outside the Araguainha crater, in the Brasília orogenic belt. The molten products are texturally distinct and different from the original rock, but have very similar geochemical composition, making it difficult to separate these lithotypes based on concentrations of major and minor elements. This also applies for trace and rare earth elements (REE), thus indicating a high degree of homogenization during impact-induced congruent melting under high pressure and postshock temperature conditions. Petrographic observations, along with geochemical data, indicate that melting occurs selectively, where some of the elements are transported with the melt. Simultaneously, there is an effective dissolution of the rock (granite), which leads to entrainment of the most resistant solid phases (intact or partially molten minerals) into the melt. Minerals more resistant to melting, such as quartz and oxides, contribute substantially to a chemical balance between the preserved granite and the fusion products generated during the meteoritic impact.

Publications - GMC 357 | Alaska Division of Geological & Geophysical

Science.gov Websites

DGGS GMC 357 Publication Details Title: Thin Section and Scanning Electron Microscopy summary Laboratories, Inc., 2008, Thin Section and Scanning Electron Microscopy summary photographs from plugs taken

Petrographic and geochemical evidence for the formation of primary, bacterially induced lacustrine dolomite: La Roda 'white earth' (Pliocene, Central Spain)

USGS Publications Warehouse

Garcia, Del; Cura, M.A.; Calvo, J.P.; Ordonez, S.; Jones, B.F.; Canaveras, J.C.

2001-01-01

Upper Pliocene dolomites ('white earth') from La Roda, Spain, offer a good opportunity to evaluate the process of dolomite formation in lakes. The relatively young nature of the deposits could allow a link between dolomites precipitated in modern lake systems and those present in older lacustrine formations. The La Roda Mg-carbonates (dolomite unit) occur as a 3??5- to 4-m- thick package of poorly indurated, white, massive dolomite beds with interbedded thin deposits of porous carbonate displaying root and desiccation traces as well as local lenticular gypsum moulds. The massive dolomite beds consist mainly of loosely packed 1- to 2-??m-sized aggregates of dolomite crystals exhibiting poorly developed faces, which usually results in a subrounded morphology of the crystals. Minute rhombs of dolomite are sparse within the aggregates. Both knobbly textures and clumps of spherical bodies covering the crystal surfaces indicate that bacteria were involved in the formation of the dolomites. In addition, aggregates of euhedral dolomite crystals are usually present in some more clayey (sepiolite) interbeds. The thin porous carbonate (mostly dolomite) beds exhibit both euhedral and subrounded, bacterially induced dolomite crystals. The carbonate is mainly Ca-dolomite (51-54 mol% CaCO3), showing a low degree of ordering (degree of ordering ranges from 0??27 to 0??48). Calcite is present as a subordinate mineral in some samples. Sr, Mn and Fe contents show very low correlation coefficients with Mg/Ca ratios, whereas SiO2 and K contents are highly correlated. ??18O- and ??13C-values in dolomites range from -3??07??? to 5??40??? PDB (mean = 0??06, ?? = 1??75) and from -6??34??? to -0??39??? PDB (mean = -3??55, ?? = 1??33) respectively. Samples containing significant amounts of both dolomite and calcite do not in general show significant enrichment or depletion in 18O and 13C between the two minerals. The correlation coefficient between ??18O and ??13C for dolomite is extremely low and negative (r = -0??05), whereas it is higher and positive (r = 0??47) for calcite. The lacustrine dolomite deposit from La Roda is interpreted mainly as a result of primary precipitation of dolomite in a shallow, hydrologically closed perennial lake. The lake was supplied by highly saturated HCO3-/CO32- groundwater that leached dolomitic Mesozoic formations. Precipitation of dolomite from alkaline lake waters took place under a semi-arid to arid climate. However, according to our isotopic data, strong evaporative conditions were not required for the formation of the La Roda dolomite. A significant contribution by bacteria to the formation of the dolomites is assumed in view of both petrographic and geochemical evidence.

Study of Hydrothermal Mineralization in 2013 Drill Core from Hawaii Island

NASA Astrophysics Data System (ADS)

Lautze, N. C.; Calvin, W. M.; Moore, J.; Haskins, E.; Thomas, D. M.

2014-12-01

The Humu'ula Groundwater Research Project (HGRP) drilled a continuously-cored hole to nearly 2 km depth near the Saddle Road between Mauna Loa and Mauna Kea volcanoes on Hawaii Island in March of 2013. Temperatures at the bottom of the hole were unexpectedly high and reached over 100 C. A study is underway to characterize hydrothermal (secondary) mineralization in the core at depths below ~ 1 km. Secondary mineralization can indicate the presence, chemistry, and temperature of hydrothermal fluids, therein helping to characterize a present and/or past geothermal system. To date, the study is two pronged. In collaboration with University Nevada Reno (UNR) we used an Analytical Spectral Devices (ASD) FieldSpec instrument to obtain nearly 800 spectra from core depths spanning 3190 to 5785 feet. This device has a 2 cm contact probe that measures from 0.4 to 2.5 mm, and has been used successfully by UNR to identify depth-associated changes in alteration mineralogy and zoning in drill core from other pilot studies. The spectra indicate that rocks above a depth of ~1 km are only weakly altered. At greater depths to the base of the well, chlorite, possibly with some mica, and zeolites are common. The majority of zeolites are spectrally similar to each other at these wavelengths, however analcime and natrolite are uniquely identified in some sections. Epidote was not observed. The secondary mineral assemblages suggest that the alteration was produced by moderate temperature neutral pH fluids. Here, we used the spectral data as a survey tool to help identify and select over 20 sections of core for sampling and more detailed mineralogical analysis using traditional X-Ray Diffraction (XRD) and petrographic techniques, conducted in collaboration with University of Utah. This presentation will include mineral maps with depth and results of the petrographic analyses.

Publications - GMC 399 | Alaska Division of Geological & Geophysical

Science.gov Websites

DGGS GMC 399 Publication Details Title: Thin section photomicrographs and descriptions for the Ikpikpuk Boyer, D., 2012, Thin section photomicrographs and descriptions for the Ikpikpuk #1, Inigok #1, J.W

Wear resistant pavement study.

DOT National Transportation Integrated Search

2009-01-01

This report documents the construction of three special pavement test sections on I-90 east of Spokane, Washington. The test sections included ultra-thin and thin whitetopping, Modified Class D open graded asphalt concrete, and micro/macro surfacing ...

Determination of fluoride source in ground water using petrographic studies in Dashtestan area, south of Iran

NASA Astrophysics Data System (ADS)

Battaleb-Looie, Sedigheh; Moore, Farid, ,, Dr.

2010-05-01

The groundwater occurs in Dashtestan area, contains a high level of fluoride. Since groundwater is vastly used for drinking and irrigation purposes, the local residents are at high risk of fluoride toxicity, as already evidenced by the occurrence of dental Fluorosis in many residents. 35 surface and groundwater samples were collected in September, 2009. The results show that in 23 samples the fluoride concentration is above the permissible level (1.5ppm). Petrographic study of lithological units in the catchment area indicates that mica minerals are the most probable source of fluoride content in the study area.

Iodine-xenon studies of petrographically and chemically characterized Chainpur chondrules

NASA Technical Reports Server (NTRS)

Swindle, T. D.; Caffee, M. W.; Hohenberg, C. M.; Lindstrom, M. M.; Taylor, G. J.

1991-01-01

INAA, noble gas, and petrographic studies conducted on samples of 18 chondrules and matric material from the Chainpur (LL3) indicate that the I-129/I-127 ratio, R(0), varies by a factor of more than 10 among the chondrules. This corresponds to a greater-than-50 Ma span in apparent I-Xe ages. Models which invoke either gas-dust mixing or nebular heterogeneity cannot satisfactorily explain these data, any more than can hypotheses which attribute the variations to differences in formation age, metamorphic rate, or time of aqueous alteration. It is alternatively suggested that the variations represent periods of low-grade shock events.

The origin, type and hydrocarbon generation potential of organic matter in a marine-continental transitional facies shale succession (Qaidam Basin, China).

PubMed

Wang, Guo-Cang; Sun, Min-Zhuo; Gao, Shu-Fang; Tang, Li

2018-04-26

This organic-rich shale was analyzed to determine the type, origin, maturity and depositional environment of the organic matter and to evaluate the hydrocarbon generation potential of the shale. This study is based on geochemical (total carbon content, Rock-Eval pyrolysis and the molecular composition of hydrocarbons) and whole-rock petrographic (maceral composition) analyses. The petrographic analyses show that the shale penetrated by the Chaiye 2 well contains large amounts of vitrinite and sapropelinite and that the organic matter within these rocks is type III and highly mature. The geochemical analyses show that these rocks are characterized by high total organic carbon contents and that the organic matter is derived from a mix of terrestrial and marine sources and highly mature. These geochemical characteristics are consistent with the results of the petrographic analyses. The large amounts of organic matter in the Carboniferous shale succession penetrated by the Chaiye 2 well may be due to good preservation under hypersaline lacustrine and anoxic marine conditions. Consequently, the studied shale possesses very good hydrocarbon generation potential because of the presence of large amounts of highly mature type III organic matter.

Cretaceous potassic intrusives with affinities to aillikites from Jharia area: Magmatic expression of metasomatically veined and thinned lithospheric mantle beneath Singhbhum Craton, Eastern India

NASA Astrophysics Data System (ADS)

Srivastava, Rajesh K.; Chalapathi Rao, N. V.; Sinha, Anup K.

2009-11-01

Cretaceous potassic dykes and sills at the Jharia area intrude the Permo-carboniferous coal-bearing Gondwana sediments of the Eastern Damodar Valley, Singhbhum craton. These intrusives are widely regarded as a part of the Mesozoic alkaline and Rajmahal flood basalt magmatism in the Eastern Indian shield. Jharia intrusives display a wide petrographic diversity; olivine, phlogopite and carbonate are the predominant phases whereas apatite and rutile constitute important accessories. Impoverishment in sodium, silica and alumina and enrichment in potassium, titanium and phosphorous are the hallmark of these rocks and in this aspect they are strikingly similar to the rift-related aillikites (ultramafic lamprophyres) of Aillik Bay, Labrador. Crustal contamination of the Jharia magmas is minimal and the incompatible trace element ratios demonstrate (i) their generation by greater degrees of partial melting of a sub-continental lithospheric mantle (SCLM) source similar to that of the kimberlites of Dharwar craton, southern India, and (ii) retention of long-term memories of ancient (Archaean) subduction experienced by their source regions. We infer that a metasomatically veined and thinned lithosphere located at the margin of the Singhbhum craton and the inheritance of an ancient (Archaean) subducted component has played a significant role in deciding the diverging petrological and geochemical characters displayed by the Jharia potassic intrusives: those of kimberlites (orangeites) and lamproites (cratonic signature) and those of aillikites (rift-related signature). A substantial melt component of Jharia potassic intrusives was derived from the SCLM and the melt contribution of the Kerguelen plume is inferred to be minimal.

7 CFR 29.3648 - Thin Leaf (C Group).

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Thin Leaf (C Group). 29.3648 Section 29.3648... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.3648 Thin Leaf (C Group). This group consists of leaves... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth...

7 CFR 29.3648 - Thin Leaf (C Group).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Thin Leaf (C Group). 29.3648 Section 29.3648... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.3648 Thin Leaf (C Group). This group consists of leaves... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth...

7 CFR 29.3648 - Thin Leaf (C Group).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Thin Leaf (C Group). 29.3648 Section 29.3648... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.3648 Thin Leaf (C Group). This group consists of leaves... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth...

7 CFR 29.3648 - Thin Leaf (C Group).

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Thin Leaf (C Group). 29.3648 Section 29.3648... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.3648 Thin Leaf (C Group). This group consists of leaves... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth...

7 CFR 29.3648 - Thin Leaf (C Group).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Thin Leaf (C Group). 29.3648 Section 29.3648... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.3648 Thin Leaf (C Group). This group consists of leaves... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth...

Acquisition of thin coronal sectional dataset of cadaveric liver.

PubMed

Lou, Li; Liu, Shu Wei; Zhao, Zhen Mei; Tang, Yu Chun; Lin, Xiang Tao

2014-04-01

To obtain the thin coronal sectional anatomic dataset of the liver by using digital freezing milling technique. The upper abdomen of one Chinese adult cadaver was selected as the specimen. After CT and MRI examinations verification of absent liver lesions, the specimen was embedded with gelatin in stand erect position and frozen under profound hypothermia, and the specimen was then serially sectioned from anterior to posterior layer by layer with digital milling machine in the freezing chamber. The sequential images were captured by means of a digital camera and the dataset was imported to imaging workstation. The thin serial section of the liver added up to 699 layers with each layer being 0.2 mm in thickness. The shape, location, structure, intrahepatic vessels and adjacent structures of the liver was displayed clearly on each layer of the coronal sectional slice. CT and MR images through the body were obtained at 1.0 and 3.0 mm intervals, respectively. The methodology reported here is an adaptation of the milling methods previously described, which is a new data acquisition method for sectional anatomy. The thin coronal sectional anatomic dataset of the liver obtained by this technique is of high precision and good quality.

The Paradox of the Axial Melt Lens: Petrology and Geochemistry of the Upper Plutonics at Hess Deep

NASA Astrophysics Data System (ADS)

Lissenberg, C. J.; Loocke, M. P.; MacLeod, C. J.

2014-12-01

The axial melt lens (AML) is a steady-state magma-rich body located at the dyke-gabbro transition at intermediate- and fast-spreading ridges. It is widely believed to be the reservoir from which mid-ocean ridge basalt (MORB) is erupted. The paradox of the axial melt lens is that the plutonic rocks that occur at this level are far too evolved to be in equilibrium with MORB, which is basaltic by definition; hence, the plutonic and volcanic records do not match. We explore this paradox by study of the first comprehensive sample suite of the uppermost plutonics of a fast-spreading ridge, taken by remotely-operated vehicle from the Hess Deep rift during cruise JC21. 23 samples (8 dolerites, 14 gabbronorites, and 1 gabbro) were collected from a section containing the transition from the uppermost gabbroic section into sheeted dykes. We present the results of a detailed petrographic and microanalytical investigation of these samples. They are dominated by evolved, varitextured (both in hand sample and thin section) oxide gabbronorites; olivine occurs in only one sample. A preponderance of the samples have positive Eu/Eu* and Sr/Sr*, indicating a cumulate origin. However, the minerals have evolved compositions, and are in equilibrium with melts significantly more evolved than East Pacific Rise MORB. Furthermore, the trace element contents of clinopyroxene differ significantly from clinopyroxene in equilibrium with MORB, being more enriched in incompatible elements. To account for both the evidence of derivation of MORB from the AML and the evolved nature of its rock record, we posit that the AML must be fed by melts on two different timescales: continual low-volume feeding by evolved interstitial melt from the cumulus pile below is augmented episodically by delivery of high volumes of more primitive melt. The latter episodes may trigger eruptions; hence the primitive melts are held in the magma chamber for only short periods, and erupt on the seafloor before significant crystallisation in the AML has taken place. This model for the feeding of the AML provides ample opportunity for mixing between the relatively primitive melts and the evolved, trace-element-rich melt, and accounts for the observed over-enrichment in incompatible elements of MORB.

Sedimentology, Mineralogy, Morphology, and Characterization of Purple Non-Sulfur Bacteria Communities from Modern Hypersaline Microbial Mats in Puerto Rico and the Virgin Islands

NASA Astrophysics Data System (ADS)

Rodriguez Colon, B. J.; Rivera-Lopez, E. O.; Ramirez-Martinez, W. R.; Rios-Velazquez, C.; Perez-Valentin, K. A.

2017-12-01

Microbial mats are organosedimentary structures which house complex guilds of microbial communities, held together by a gelatinous exopolymeric substance (EPS). This biofilm contributes to the formation of laminations by binding and trapping sediments, as well as in-situ organomineralization. Microbial mats commonly thrive in extreme habitats, such as the hypersaline environments, which have been studied throughout several coastal regions in the Caribbean. This project aims to study the morphology, sedimentology, and mineralogy of five different modern hypersaline microbial mats from Puerto Rico and Anegada that have not yet been studied, to assess their differences/similarities. At the same time, we intent to isolate and characterize purple non-sulfur bacteria (PNSB), which is an anoxyphototrophic microorganism that contributes to the pink pigmentation observed in the second layer of a typical microbial mat. Different layers within each mat were separated, dissected and dissolved to remove all organic material. The resulting sediment was then analyzed mineralogically using X-ray diffraction, and used to make petrographic thin sections. To isolate PNSB candidates, serial dilutions followed by filtration were performed to extracted sections from the pink layer of each mat. The samples were planted in Petri dishes with marine media and placed in Anaerobic Jars. Colonies Descriptions, Gram stain and molecular analysis using 16S rDNA gene was performed. Preliminary results show a diversity of mat morphologies throughout the ponds, similar to what has been observed in other hypersaline ponds and marshes in the Caribbean. Sedimentary analysis shows that the mats from Puerto Rico have similar allochthonous material (e.g. Halimeda sp. fragments). Microcodium fabrics, conoform structures, and hemispheroidal morphologies were observed as well. In Anegada, lithified microbialites were observed in the Red Pond location. Mineralogically, all samples were similar except for the mats in Cabo Rojo, Puerto Rico, which contained allochthonous quartz. 38 possible PNSB candidates were isolated from the mats, showing similar colonial characteristics (convex elevations, entire margins and pink pigmentations). Molecular results will be shown during the meeting.

The Cretaceous glauconitic sandstones of Abu Tartur, Egypt

NASA Astrophysics Data System (ADS)

Pestitschek, Brigitte; Gier, Susanne; Essa, Mahmoud; Kurzweil, Johannes

2010-05-01

The Abu Tartur mine is located in the Western Desert of Egypt, 50 km west of El Kharga City. Geologically, the Abu Tartur plateau is built by a sequence of Upper Cretaceous (Campanian - Maastrichtian) phosphorites, black shales and glauconitic sandstones. The phosphate deposits are of great economic importance and have been mined since their discovery in 1967. Outcrop sections were measured, sampled, sedimentologically characterized and described. One specific glaucony layer was investigated mineralogically and chemically in detail and compared to a subsurface sample from the mine. Two depositional regimes can be interpreted based on sedimentary architecture and structures: 1) a deeper-water hemipelagic environment, where phosphorites and organic carbon-rich shales were deposited and 2) a shallower, prograding higher energy shelf environment with glauconies. From a sequence stratigraphic perspective 1) was deposited during the transgressive systems tract and the early highstand while 2) was deposited during the remaining highstand and a lowstand prograding wedge (Glenn & Arthur, 1990). Petrographic and SEM investigations show that the glaucony grains are of authochtonous origin. XRF, EMPA and thin-section analyses show that the glaucony grains from the outcrop differ significantly in their chemical composition, morphology and color from the grains of the mine sample. The fresh glauconies are enriched in Fe2O3 and K2O compared to the surface samples. XRD analyses of the clay fraction of the six outcrop samples and the mine sample show that the grains consist of illite(glauconite)/smectite mixed-layers, with more illite layers (80 %) in the mine sample. The charge distribution diagram muscovite-pyrophyllite-celadonite shows a clear trend from smectitic glaucony to illitic glaucony, the mine sample plots exactly in the field for glauconites. All these features indicate that the surface samples are strongly altered by weathering and that glauconite progressively transforms into iron-rich illte/smectite mixed layers and then into smectites. For any chemical and mineralogical characterization of glauconites at surface, these weathering effects have to be taken into consideration. GLENN, C. R. & ARTHUR, M. A. (1990): Anatomy and origin of a Cretaceous phosphorites-greensand giant, Egypt. Sedimentology, 37, 123-154.

EBSD characterization of pre-Cambrian deformations in conglomerate pebbles (Sierra de la Demanda, Northern Spain)

NASA Astrophysics Data System (ADS)

Puelles, Pablo; Ábalos, Benito; Fernández-Armas, Sergio

2010-05-01

Pre-Cambrian and unconformable earliest Cambrian rocks from the Sierra de la Demanda (N Spain) exhibit field and microstructural relationships that attest to orogenic events recorded by concealed basement rocks. Neoproterozoic foliated slates ("Anguiano Schists") crop out under up to 300 m thick, unfoliated quartz-rich conglomerates ("Anguiano Conglomerates") and quartzites which are stratigraphically ca. 600 m below the oldest, paleontologically dated, pre-trilobitic Cambrian layers (likely older than 520 Ma). The Anguiano Conglomerates contain mm to cm grainsized well-rounded pebbles of various types including monocrystalline quartz, detrital zircon and tourmaline-bearing sandstones, black cherts and metamorphic poly-crystalline quartz aggregates. The undeformed matrix is made of much smaller (diagenetically overgrown) monocrystaline quartz grains and minor amounts of accesory zircon, tourmaline and mica. Black chert pebbles exhibit microstructural evidence of brittle deformation (microfaults and thin veins of syntaxial fibrous quartz). These and the fine-grained sandstone pebbles can also exhibit ductile deformations (microfolds with thickened hinges and axial planar continuous foliations), too. Polycrystalline quartz pebbles exhibit a variety of microstructures that resulted from syn-metamorphic ductile deformations. These are recognisable under the petrographic microscope and include continuous foliations, quartz shape fabrics, various types of subgrain or recrystallized new grain microtextures, and lattice preferred orientations (LPOs). Conventional characterization of quartz fabrics (after oriented structural sections) is challenged in conglomerate pebble thin sections by the difficulty of unraveling in them the complete structural reference framework provided by foliation (whose trace can be unraveled) and lineation orientation (which cannot be directly identified). Quartz in various metamorphic polycrystalline pebbles was studied with the Electron Back-Scatter Diffraction (EBSD) technique. The identification of quartz c-axis point maxima or girdles and their geometrical relationships with respect to -axis arrangements and pebble foliation traces enabled us to identify the operation of basal and prism- and occasionally prism-[c] intracrystalline slip systems. This points to upper-greenschists and amphibolite facies syn-metamorphic deformations. By contrast, black chert and sandstone pebbles and matrix quartz aggregates lack any LPO. The source area of the conglomerates was likely a pre-Cambrian basement that contained penetratively deformed low- to medium-grade metamorphic rocks. Radiometric dating of this metamorphism has not been accomplished so far though it is known that inherited Precambrian sources in the Iberian Peninsula relate notably to Neoproterozoic (Pan-African and Cadomian) orogens, and to a lesser extent to Paleoproterozoic (1.8-2.1 Ga) or Neoarchean (2.4-2.8 Ga) ones. Neoproterozoic (Cadomian) metamorphism of this grade has only been recognized in SW Iberia. If the fabrics here studied were Cadomian, they might be related to the arc-related igneous suites that have been detected or inferred in other realms of the northern Iberian Massif.

Black and red granites in the Egyptian Antiquity Museum of Turin. A minero-petrographic and provenance study.

NASA Astrophysics Data System (ADS)

Serra, M.; Borghi, A.; Vaggelli, G.; D'Amicone, E.; Vigna, L.

2009-04-01

The University of Turin, in cooperation with the Egyptian Antiquity Museum, has recently undertaken several projects aimed at developing a scientific approach to the analysis of ancient Egyptian finds. In particular, a straightforward project to investigate the stony handcrafts preserved in the statuary rooms started in 2006 to obtain their systematic petrographic classification and their possible geological sources. The main intent of the project was to understand the provenance of the materials used in Pharaonic period, setting the base for the identification of the ancient quarry sites and for a correct interpretation of the extraction and working techniques, in order to provide fundamental information about economical and social development of Egyptian civilization through historical times. The choice to focus attention on black and red granites came from the statement of the percentage relevance (40 of the 54 sculptures actually exposed) of these materials in the statuary rooms. Moreover, especially for black granites, the need of detailed minero-petrographic analysis arose from the difficulty in making a macroscopic classification of the fine-grained dark-coloured rock varieties. Therefore, five black granite statues, belonging to the Drovetti collection were sampled in a micro-invasive way: three sculptures of goddess Sekhmet (cat. 260, 251, 247), the statue of Ramses II (cat. 1380) and the statue of goddess Hathor (cat. 694). The choice to analyse even three of the twenty-one statues of goddess Sekhmet (cat. 247, cat. 251, cat. 260), originally located in the same Egyptian temple but ichnographically different, derived from the need of answering the archaeological questions about their provenance. On the other hand, the opportunity of studying the fine-grained black rocks used for the sculptures of goddess Hathor (cat. 694) and of Ramses II in Majesty (cat. 1380), symbol of the Egyptian museum of Turin, provided the opportunity to analyse and classify the materials used for two of the best known masterpieces of Egyptian art. As regards to red granites, it has been observed that most of the exposed sculptures were made of rocks closely akin to Aswan granite. Just in one case, the Ram headed sphinx (cat. 836), macroscopic differences in colour index, grain size and isoorientation of feldspar phenocrysts, suggested a different provenance of the source material and determined the choice of picking up a small fragment for minero-petrographic analysis. The sample collected from the sarcophagus of Nefertari (suppl. 5153) during the recent restoration of the sculpture, was analysed in order to test the accuracy of the results, as the provenance of the material used for its realization was already certain. Petrographic observations and chemical analysis were undertaken by a scanning electron microscope equipped with an energy-dispersive spectrometer. Minero-petrographic data primarily showed that all samples vary in composition from granite (red granites) to granodiorite and tonalite (black granites). The main sialic phases are represented by plagioclase (albite to oligoclase), alkali-feldspar (microcline) and quartz, while femic phases are amphibole (green horneblende) and biotite (Fe- to Mg-biotite), always coexisting in variable relative percentages. Minor amount of apatite (≈ 1 wt.%), magnetite, ilmenite, often associated to sphene, zircon, pyrite and allanite also occur. The identification of some compositional markers in all samples suggested a common provenance for all the rocks used for the sculptures. Thus, it was supposed that they could all have been quarried in the famous district of Aswan, well known at least since Dynastic period. This provenance hypothesis was confirmed by geological literature and archeological evidences, considering the relative proximity of Aswan quarries to Nile river and to the key centres of power in the New Kingdom. Therefore, several geological samples were collected in Aswan area, in order to perform a minero - petrographical and geochemical comparison with the rocks of the statues. According to the petrographic and minero-chemical results, it was possible to define the provenance of the granitoids used for the realization of the sculptures and finally to highlight the importance of an archaeometric approach to historical and archaeological problems.

Original structures, and fragmentation and reassembly histories of asteroids - Evidence from meteorites

NASA Technical Reports Server (NTRS)

Taylor, G. Jeffrey; Maggiore, Peter; Scott, Edward R. D.; Rubin, Alan E.; Keil, Klaus

1987-01-01

The validity of an onion shell model (OSM) for chondrite parent asteroids was assessed using metallographic cooling rates (MCR) derived from the compositions of metallic Fe-Ni grains. The hypothesis evaluated was that the hottest materials in chondrites would have been buried the deepest and cooled the slowest. The survey covered breccia from regolith and 13 different chondrites. The MCRs agreed well with cooling rates predicted by fission-track thermometry and Ar-40/Ar-39 ages. The OSM predicts an inverse correlation between the cooling rate and the petrographic type. Low correlations found between the MCRs and petrographic type indicate that chondrite parent asteroids were not assembled with onion shell structures.

The Apollo 16 regolith - A petrographically-constrained chemical mixing model

NASA Technical Reports Server (NTRS)

Kempa, M. J.; Papike, J. J.; White, C.

1980-01-01

A mixing model for Apollo 16 regolith samples has been developed, which differs from other A-16 mixing models in that it is both petrographically constrained and statistically sound. The model was developed using three components representative of rock types present at the A-16 site, plus a representative mare basalt. A linear least-squares fitting program employing the chi-squared test and sum of components was used to determine goodness of fit. Results for surface soils indicate that either there are no significant differences between Cayley and Descartes material at the A-16 site or, if differences do exist, they have been obscured by meteoritic reworking and mixing of the lithologies.

Cometary particles - Thin sectioning and electron beam analysis

NASA Technical Reports Server (NTRS)

Bradley, J. P.; Brownlee, D. E.

1986-01-01

Thin sections (500 to 1000 angstroms thick) of individual micrometeorites (5 to 15 micrometers) have been prepared with an ultramicrotome equipped with a diamond knife. Electron microscope examination of these sections has revealed the internal structures of chondritic micrometeorites, and a subset of highly porous, fragile particles has been identified. Delicate meteoritic materials such as these are characteristic of debris from cometary meteors.

The application of artificial intelligence for the identification of the maceral groups and mineral components of coal

NASA Astrophysics Data System (ADS)

Mlynarczuk, Mariusz; Skiba, Marta

2017-06-01

The correct and consistent identification of the petrographic properties of coal is an important issue for researchers in the fields of mining and geology. As part of the study described in this paper, investigations concerning the application of artificial intelligence methods for the identification of the aforementioned characteristics were carried out. The methods in question were used to identify the maceral groups of coal, i.e. vitrinite, inertinite, and liptinite. Additionally, an attempt was made to identify some non-organic minerals. The analyses were performed using pattern recognition techniques (NN, kNN), as well as artificial neural network techniques (a multilayer perceptron - MLP). The classification process was carried out using microscopy images of polished sections of coals. A multidimensional feature space was defined, which made it possible to classify the discussed structures automatically, based on the methods of pattern recognition and algorithms of the artificial neural networks. Also, from the study we assessed the impact of the parameters for which the applied methods proved effective upon the final outcome of the classification procedure. The result of the analyses was a high percentage (over 97%) of correct classifications of maceral groups and mineral components. The paper discusses also an attempt to analyze particular macerals of the inertinite group. It was demonstrated that using artificial neural networks to this end makes it possible to classify the macerals properly in over 91% of cases. Thus, it was proved that artificial intelligence methods can be successfully applied for the identification of selected petrographic features of coal.

A petrographical and geochemical study of quartzose nodules, country rocks, and dike rocks from the Upheaval Dome structure, Utah

NASA Astrophysics Data System (ADS)

Koeberl, Christian; Plescia, J. B.; Hayward, Chris L.; Reimold, Wolf Uwe

1999-11-01

Upheaval Dome, in Canyonlands National Park, Utah, USA, is a unique structure on the Colorado Plateau. It has earlier been interpreted as an impact structure or as a pinched-off salt diapir. Some subrounded quartzose fragments were found in a ring depression near the eastern margin of the structure and, based on vesicularity and apparent flow structure, the fragments were earlier interpreted researchers as "impactites". Our petrographic studies show no indication of a high-temperature history and are in agreement with a slow, low-temperature formation of the quartz nodules. Compositionally, the lag deposit samples are almost pure SiO2. They show no chemical similarity to any of the possible target rocks (e.g., Navajo Sandstone), from which they should have formed by melting if they were impactites. Instead, the samples have relatively high contents of elements that indicate fluid interaction (e.g., hydrothermal growth), such as As, Sb, Ba, and U, and show positive Ce anomalies. Thus, we interpret the "lag deposit samples" as normal low-temperature (hydrothermally-grown?) quartz that show no indication of being impact-derived. In addition, a petrographic and geochemical analysis of a series of dike samples yielded no evidence for shock metamorphism or a meteoritic component.

Organic petrology and coalbed gas content, Wilcox Group (Paleocene-Eocene), northern Louisiana

USGS Publications Warehouse

Hackley, Paul C.; Warwick, Peter D.; Breland, F. Clayton

2007-01-01

Wilcox Group (Paleocene–Eocene) coal and carbonaceous shale samples collected from four coalbed methane test wells in northern Louisiana were characterized through an integrated analytical program. Organic petrographic analyses, gas desorption and adsorption isotherm measurements, and proximate–ultimate analyses were conducted to provide insight into conditions of peat deposition and the relationships between coal composition, rank, and coalbed gas storage characteristics. The results of petrographic analyses indicate that woody precursor materials were more abundant in stratigraphically higher coal zones in one of the CBM wells, consistent with progradation of a deltaic depositional system (Holly Springs delta complex) into the Gulf of Mexico during the Paleocene–Eocene. Comparison of petrographic analyses with gas desorption measurements suggests that there is not a direct relationship between coal type (sensu maceral composition) and coalbed gas storage. Moisture, as a function of coal rank (lignite–subbituminous A), exhibits an inverse relationship with measured gas content. This result may be due to higher moisture content competing for adsorption space with coalbed gas in shallower, lower rank samples. Shallower (< 600 m) coal samples consistently are undersaturated with respect to CH4 adsorption isotherms; deeper (> 600 m) coal samples containing less moisture range from under- to oversaturated with respect to their CH4adsorption capacity.

A petrographical and geochemical study of quartzose nodules, country rocks, and dike rocks from the Upheaval Dome structure, Utah

USGS Publications Warehouse

Koeberl, C.; Plescia, J.B.; Hayward, C.L.; Reimold, W.U.

1999-01-01

Upheaval Dome, in Canyonlands National Park, Utah, USA, is a unique structure on the Colorado Plateau. It has earlier been interpreted as an impact structure or as a pinched-off salt diapir. Some subrounded quartzose fragments were found in a ring depression near the eastern margin of the structure and, based on vesicularity and apparent flow structure, the fragments were interpreted by early researchers as 'impactites.' Our petrographic studies show no indication of a high-temperature history and are in agreement with a slow, low-temperature formation of the quartz nodules. Compositionally, the lag deposit samples are almost pure SiO2. They show no chemical similarity to any of the possible target rocks (e.g., Navajo Sandstone), from which they should have formed by melting if they were impactites. Instead, the samples have relatively high contents of elements that indicate fluid interaction (e.g., hydrothermal growth), such as As, Sb, Ba, and U, and show positive Ce anomalies. Thus, we interpret the 'lag deposit samples' as normal low-temperature (hydrothermally-grown?) quartz that show no indication of being impact-derived. In addition, a petrographic and geochemical analysis of a series of dike samples yielded no evidence for shock metamorphism or a meteoritic component.

Structure and Assembly of Intracellular Mature Vaccinia Virus: Thin-Section Analyses

PubMed Central

Griffiths, Gareth; Roos, Norbert; Schleich, Sybille; Locker, Jacomine Krijnse

2001-01-01

In the preceding study (see accompanying paper), we showed by a variety of different techniques that intracellular mature vaccinia virus (vaccinia IMV) is unexpectedly complex in its structural organization and that this complexity also extends to the underlying viral core, which is highly folded. With that analysis as a foundation, we now present different thin-section electron microscopy approaches for analyzing the IMV and the processes by which it is assembled in infected HeLa cells. We focus on conventional epoxy resin thin sections as well as cryosections to describe key intermediates in the assembly process. We took advantage of streptolysin O's ability to selectively permeabilize the plasma membrane of infected cells to improve membrane contrast, and we used antibodies against bone fide integral membrane proteins of the virus to unequivocally identify membrane profiles in thin sections. All of the images presented here can be rationalized with respect to the model put forward for the assembly of the IMV in the accompanying paper. PMID:11602745

Reduced Dimensionality Lithium Niobate Microsystems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eichenfield, Matt

2017-01-01

The following report describes work performed under the LDRD program at Sandia National Laboratories October 2014 and September 2016. The work presented demonstrates the ability of Sandia Labs to develop state-of-the-art photonic devices based on thin film lithium niobate (LiNbO 3 ). Section 1 provides an introduction to integrated LiNbO 3 devices and motivation for developing thin film nonlinear optical systems. Section 2 describes the design, fabrication, and photonic performance of thin film optical microdisks fabricated from bulk LiNbO 3 using a bulk implantation method developed at Sandia. Sections 3 and 4 describe the development of similar thin film LiNbOmore » 3 structures fabricated from LiNbO 3 on insulator (LNOI) substrates and our demonstration of optical frequency conversion with state-of-the-art efficiency. Finally, Section 5 describes similar microdisk resonators fabricated from LNOI wafers with a buried metal layer, in which we demonstrate electro-optic modulation.« less

Thin Film Ceramic Strain Sensor Development for High Temperature Environments

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Fralick, Gustave C.; Gonzalez, Jose M.; Laster, Kimala L.

2008-01-01

The need for sensors to operate in harsh environments is illustrated by the need for measurements in the turbine engine hot section. The degradation and damage that develops over time in hot section components can lead to catastrophic failure. At present, the degradation processes that occur in the harsh hot section environment are poorly characterized, which hinders development of more durable components, and since it is so difficult to model turbine blade temperatures, strains, etc, actual measurements are needed. The need to consider ceramic sensing elements is brought about by the temperature limits of metal thin film sensors in harsh environments. The effort at the NASA Glenn Research Center (GRC) to develop high temperature thin film ceramic static strain gauges for application in turbine engines is described, first in the fan and compressor modules, and then in the hot section. The near-term goal of this research effort was to identify candidate thin film ceramic sensor materials and provide a list of possible thin film ceramic sensor materials and corresponding properties to test for viability. A thorough literature search was conducted for ceramics that have the potential for application as high temperature thin film strain gauges chemically and physically compatible with the NASA GRCs microfabrication procedures and substrate materials. Test results are given for tantalum, titanium and zirconium-based nitride and oxynitride ceramic films.

The formation and alteration of the Renazzo-like carbonaceous chondrites I: Implications of bulk-oxygen isotopic composition

NASA Astrophysics Data System (ADS)

Schrader, Devin L.; Franchi, Ian A.; Connolly, Harold C., Jr.; Greenwood, Richard C.; Lauretta, Dante S.; Gibson, Jenny M.

2011-01-01

To better understand the role of aqueous alteration on the CR chondrite parent asteroid, a whole-rock oxygen isotopic study of 20 meteorites classified as Renazzo-like carbonaceous chondrites (CR) was conducted. The CR chondrites analyzed for their oxygen isotopes were Dhofar 1432, Elephant Moraine (EET) 87770, EET 92042, EET 96259, Gao-Guenie (b), Graves Nunataks (GRA) 95229, GRA 06100, Grosvenor Mountains (GRO) 95577, GRO 03116, LaPaz Ice Field (LAP) 02342, LAP 04720, Meteorite Hills (MET) 00426, North West Africa (NWA) 801, Pecora Escarpment (PCA) 91082, Queen Alexandra Range (QUE) 94603, QUE 99177, and Yamato-793495 (Y-793495). Three of the meteorites, Asuka-881595 (A-881595), GRA 98025, and MET 01017, were found not to be CR chondrites. The remaining samples concur petrographically and with the well-established oxygen-isotope mixing line for the CR chondrites. Their position along this mixing line is controlled both by the primary oxygen-isotopic composition of their individual components and their relative degree of aqueous alteration. Combined with literature data and that of this study, we recommend the slope for the CR-mixing line to be 0.70 ± 0.04 (2σ), with a δ 17O-intercept of -2.23 ± 0.14 (2σ). Thin sections of Al Rais, Shişr 033, Renazzo, and all but 3 samples analyzed for oxygen isotopes were studied petrographically. The abundance of individual components is heterogeneous among the CR chondrites, but FeO-poor chondrules and matrix are the most abundant constituents and therefore, dominate the whole-rock isotopic composition. The potential accreted ice abundance, physico-chemical conditions of aqueous alteration (e.g. temperature and composition of the fluid) and its duration control the degree of alteration of individual CR chondrites. Combined with literature data, we suggest that LAP 02342 was exposed to lower temperature fluid during alteration than GRA 95229. With only two falls, terrestrial alteration of the CR chondrites complicates the interpretation of their whole rock isotopic composition, particularly in the most aqueously altered samples, and those with relatively higher matrix abundances. We report that QUE 99177 is the isotopically lightest whole rock CR chondrite known (δ 18O = -2.29‰, δ 17O = -4.08‰), possibly due to isotopically light unaltered matrix; which shows that the anhydrous component of the CR chondrites is isotopically lighter than previously thought. Although it experienced aqueous alteration, QUE 99177 provides the best approximation of the pristine CR-chondrite parent body's oxygen-isotopic composition, before aqueous alteration took place. Using this value as a new upper limit on the anhydrous component of the CR chondrites, water/rock ratios were recalculated and found to be higher than previously thought; ratios now range from 0.281 to 1.157. We also find that, according to their oxygen isotopes, a large number of CR chondrites appear to be minimally aqueously altered; although sample heterogeneity complicates this interpretation.

Geophysical Modelling and Multi-Scale Studies in the Arctic Seiland Igneous Province: Millimeter to Micrometer Scale Mapping of the Magnetic Sources by High Resolution Magnetic Microscopy

NASA Astrophysics Data System (ADS)

Pastore, Z.; Church, N. S.; McEnroe, S. A.; Oda, H.; ter Maat, G. W.

2017-12-01

Rocks samples can have wide range of magnetic properties depending on composition, amount of ferromagnetic minerals, grain sizes and microstructures. These influence the magnetic anomalies from the micro to the global scale making the study of the magnetic properties of interest for multiple applications. Later geological processes such as serpentinization can significantly influence these properties and change the nature of the magnetic anomalies. Particularly, magnetic properties such as remanent magnetization and magnetic susceptibility are directly linked to the magnetic mineralogy composition and grain size and can provide useful information about the geological history of the source. Scanning magnetic microscopy is a highly sensitive and high-resolution magnetometric technique for mapping the magnetic field over a planar surface of a rock sample. The device measures the vertical component of the field above the thin sections and the technique offers a spatial resolution down to tens of micrometers and thus can be used to investigate discrete magnetic mineral grains or magnetic textures and structures, and the magnetic history of the sample. This technique allows a direct correlation between the mineral chemistry (through both electron and optical microscopy) and the magnetic properties. We present as case-study three thin section magnetic scans of two dunite samples from the Reinfjord Ultramafic complex, in northern Norway. The selected thin sections show different magnetic properties which reflect the magnetic petrology. One of the thin sections is from a pristine dunite sample; the other two are highly serpentinized with newly formed magnetite found in multiple, few micrometer thick, veins. We present the preliminary results obtained applying a forward modelling approach on the magnetic anomaly maps acquired over the thin sections. Modelling consists of uniformly-magnetized polygonal bodies whose geometry is constrained by the thickness of the thin section and by the shape of the magnetic grains. The NRM direction in each polygon is modelled to fit the NRM magnetic field. Modelling helps in determining the NRM directions and intensities of discrete magnetic sources inside the thin sections and thus contributes to the study of the link between the magnetic petrology and the magnetic anomalies.

Crystallisation sequence and magma evolution of the De Beers dyke (Kimberley, South Africa)

NASA Astrophysics Data System (ADS)

Soltys, Ashton; Giuliani, Andrea; Phillips, David

2018-06-01

We present petrographic and mineral chemical data for a suite of samples derived from the De Beers dyke, a contemporaneous, composite intrusion bordering the De Beers pipe (Kimberley, South Africa). Petrographic features and mineral compositions indicate the following stages in the evolution of this dyke: (1) production of antecrystic material by kimberlite-related metasomatism in the mantle (i.e., high Cr-Ti phlogopite); (2) entrainment of wall-rock material during ascent through the lithospheric mantle, including antecrysts; (3) early magmatic crystallisation of olivine (internal zones and subsequently rims), Cr-rich spinel, rutile, and magnesian ilmenite, probably on ascent to the surface; and (4) crystallisation of groundmass phases (i.e., olivine rinds, Fe-Ti-rich spinels, perovskite, apatite, monticellite, calcite micro-phenocrysts, kinoshitalite-phlogopite, barite, and baddeleyite) and the mesostasis (calcite, dolomite, and serpentine) on emplacement in the upper crust. Groundmass and mesostasis crystallisation likely forms a continuous sequence with deuteric/hydrothermal modification. The petrographic features, mineralogy, and mineral compositions of different units within the De Beers dyke are indistinguishable from one another, indicating a common petrogenesis. The compositions of antecrysts (i.e., high Cr-Ti phlogopite) and magmatic phases (e.g., olivine rims, magnesian ilmenite, and spinel) overlap those from the root zone intrusions of the main Kimberley pipes (i.e., Wesselton, De Beers, Bultfontein). However, the composition of these magmatic phases is distinct from those in `evolved' intrusions of the Kimberley cluster (e.g., Benfontein, Wesselton water tunnel sills). Although the effects of syn-emplacement flow processes are evident (e.g., alignment of phases parallel to contacts), there is no evidence that the De Beers dyke has undergone significant pre-emplacement crystal fractionation (e.g., olivine, spinel, ilmenite). This study demonstrates the requirement for detailed petrographic and mineral chemical studies to assess whether individual intrusions are in fact `evolved'; and that dykes are not necessarily produced by differentiated magmas.

One-dimensional analysis of filamentary composite beam columns with thin-walled open sections

NASA Technical Reports Server (NTRS)

Lo, Patrick K.-L.; Johnson, Eric R.

1986-01-01

Vlasov's one-dimensional structural theory for thin-walled open section bars was originally developed and used for metallic elements. The theory was recently extended to laminated bars fabricated from advanced composite materials. The purpose of this research is to provide a study and assessment of the extended theory. The focus is on flexural and torsional-flexural buckling of thin-walled, open section, laminated composite columns. Buckling loads are computed from the theory using a linear bifurcation analysis and a geometrically nonlinear beam column analysis by the finite element method. Results from the analyses are compared to available test data.

Petrographic and Geochemical Characterization of the Cambumbia STOCK in Andean Central Cordillera, Colombia

NASA Astrophysics Data System (ADS)

Rojas Lequerica, S.; Jaramillo Mejía, J.; Concha Perdomo, A.

2012-12-01

The Cambumbia Stock is located on the western flank of the Central Cordillera of the northern Andes. The goals of this study were to petrographic and geochemically characterize the Cambumbia igneous body and to establish its petrogenetic history. 41 samples were collected, 28 for petrographic analysis and 14 for elementary chemical determination by ICP-MS. Petrographically the samples were classified as hornblende and pyroxene-gabbros varying to diorites, gabbronorites and tonalites, the rock texture varies from medium to coarse granular grain, with local microporfiritic texture. It was concluded from the major elements analysis that the samples correspond to the sub-alkaline series with low K content, mainly in the calc-alkaline series, within the gabbros and diorites fields. By using the SiO2 vs TiO2 (Jaramillo, 1980), Th/Yb vs Ta/Yb (Pearce, 1984) (Fig. 1) and Zr/117-Th-Nb/16 (Wood, 1979) diagrams it was determined that these rocks were generated in two geotectonic environments: one type MOR (extension) and other island arc (subduction, compression). Petrographic and geochemical comparisons between the rocks of Cambumbia Stock and Diorite and Gabbro El Pueblito (Giraldo, 2009) (located about 25 km to the north-west) may postulate a possible genetic link between them. Recently, a U/Pb age was obtained by the Universidad de Caldas in zircon in 2009 (not published data), yielded an age of 233.41 ± 3.4 Ma (Middle Triassic). This age is consistent with the global event of the extension and fragmentation of Pangea supercontinent. In addition, the mantle nature of the source and the petrogenetic evolution of the magmatic system were established. References GIRALDO, M.I., (2009): Esquema geodinámica de la parte noroccidental de la cordillera Central de Colombia. (Thesis). p.56-68. Universidad Nacional de Colombia, Medellín. JARAMILLO, J.M. (1980): Petrology and geochemistry of the Nevado del Ruiz Volcano northern Andes, Colombia (Thesis). 167 p. University of Houston, Faculty of the Department of Geology, Houston. PEARCE, J.A., HARRIS, N.B.W., and TINDLE, A.G., (1984), Trace element discrimination diagrams for the tectonic interpretation: Journal of Petrology, v. 25, p. 956-983. WOOD, D., JORON, J.L., & TREUIL, M. (1979): A re-appaisal of the use of trace elements to classify and discriminate between magma series erupted in different tectonic settings. Earth Planet Sci. Lett., 326-336. Th/Yb Vs Ta/Yb diagram

Calculation of Centrally Loaded Thin-Walled Columns Above the Buckling Limit

NASA Technical Reports Server (NTRS)

Reinitzhuber, F.

1945-01-01

When thin-walled columns formed from flanged sheet, such as used in airplane construction, are subjected to axial load, their behavior at failure varies according to the slenderness ratio. On long columns the axis deflects laterally while the cross section form is maintained; buckling results. The respective breaking load in the elastic range is computed by Euler's formula and for the plastic range by the Engesser- Karman formula. Its magnitude is essentially dependent upon the length. On intermediate length columns, especially where open sections are concerned, the cross section is distorted while the cross section form is preserved; twisting failure results. The buckling load in twisting is calculated according to Wagner and Kappus. On short columns the straight walls of low-bending resistance that form the column are deflected at the same time that the cross section form changes - buckling occurs without immediate failure. Then the buckling load of the total section computable from the buckling loads of the section walls is not the ultimate load; quite often, especially on thin-walled sections, it lies considerably higher and is secured by tests. Both loads, the buckling and the ultimate load are only in a small measure dependent upon length. The present report is an attempt to theoretically investigate the behavior of such short, thin-walled columns above the buckling load with the conventional calculating methods.

Minor Elements in Nakhlite Pyroxenes: Cr in MIL00346

NASA Technical Reports Server (NTRS)

McKay, G. A.; Schwandt, C.; Le, L.; Makishima, J.; Kurihara, T.

2006-01-01

Nakhlites are olivine-bearing clinopyroxene cumulates. Based on petrographic characteristics, they may be divided into groups that cooled at different rates and may have been formed at different depths in a single flow. The order of cooling rate from slowest to fastest is NWA998

The Carbonates in ALH 84001 Record the Evolution of the Martian Atmosphere Through Multiple Formation Events

NASA Technical Reports Server (NTRS)

Shaheen, R.; Niles, P. B.; Corrgan, C.

2012-01-01

Current Martian conditions restrict the presence of liquid water due to low temperatures (approx 210K), a thin atmosphere (approx 7mb), and intense UV radiation. However, past conditions on Mars may have been different with the possibility that the ancient Martian climate was warm and wet with a dense CO2 atmosphere. The cycling of carbon on Mars through atmospheric CO2 and carbonate minerals is critical for deciphering its climate history. In particular stable isotopes contained in carbonates can provide information of their origin and formation environment as well as possibly hinting at the composition of global reservoirs such as atmospheric CO2. Martian meteorite ALH 84001 contains widely studied carbonate rosettes that have been dated to approx. 3.9 Ga and have been used to interpret climatic conditions present at that time. However, there is mount-ing evidence for multiple episodes of carbonate formation in ALH 84001 with potentially distinct isotopic compositions. This study seeks to tease out these different carbonate assemblages using stepped phosphoric acid dissolution and analysis of carbon and triple oxygen stable isotopes. In addition, we report SIMS analyses of the delta O-18 several petrographically unusual carbonate phases in the meteorite.

Radiation and scattering by thin-wire structures in the complex frequency domain. [electromagnetic theory for thin-wire antennas

NASA Technical Reports Server (NTRS)

Richmond, J. H.

1974-01-01

Piecewise-sinusoidal expansion functions and Galerkin's method are employed to formulate a solution for an arbitrary thin-wire configuration in a homogeneous conducting medium. The analysis is performed in the real or complex frequency domain. In antenna problems, the solution determines the current distribution, impedance, radiation efficiency, gain and far-field patterns. In scattering problems, the solution determines the absorption cross section, scattering cross section and the polarization scattering matrix. The electromagnetic theory is presented for thin wires and the forward-scattering theorem is developed for an arbitrary target in a homogeneous conducting medium.

Strength Tests on Thin-walled Duralumin Cylinders in Torsion

NASA Technical Reports Server (NTRS)

Lundquist, Eugene E

1932-01-01

This report is the first of a series presenting the results of strength tests on thin-walled cylinders and truncated cones of circular and elliptical section; it comprises the results obtained to date from torsion (pure shear) tests on 65 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. The effect of variations in the length/radius and radius/thickness ratios on the type of failure is indicated, and a semi-empirical equation for the shearing stress at maximum load is given.

75 FR 29974 - Application(s) for Duty-Free Entry of Scientific Instruments

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-28

... portions of vertebrate and invertebrate organisms embedded in plastic resins and cut into thin sections... vertebrate and invertebrate organisms embedded in plastic resins and cut into thin sections mounted on... Use: The instrument will be used to examine portions of vertebrate and invertebrate organisms embedded...

Astronomy through the microscope: A workshop during the opening night of the 2016 IMC

NASA Astrophysics Data System (ADS)

Netjes, G. J.; de Vet, S.

2016-01-01

During the IMC workshop meteoritical thins sections were shown live with a microscope connected to the beamer. This article will provide a background to thin sections, what we can learn from them and the tour through the solar system we can take with them.

Ureilite Thin Section Preparation

NASA Technical Reports Server (NTRS)

Harrington, R.; Righter, K.

2014-01-01

Preparing thin and thick sections of ureilite type meteorites is a challenge that can confound even the most experienced section preparer. A common characteristic of these samples is the presence of carbon phases, particularly nanodiamonds, in the matrix along silicate grain boundaries, fractures, and cleavage plains [1]. The extreme hardness of the nanodiamonds presents a challenge to the section preparer in the form of high surface relief on the section. This hard material also causes considerable wear and tear on equipment and materials that are used for making the sections. These issues will be discussed and potentially helpful measures will be presented.

Pristine nonmare rocks and the nature of the lunar crust

NASA Technical Reports Server (NTRS)

Warren, P. H.; Wasson, J. T.

1977-01-01

It is shown that the interdisciplinary study of the nonmare lunar rocks based on trace element, major element, and isotopic data plus petrographic evidence can succeed in amassing a large suite of demonstrably pristine rocks, and that the relative numbers of these rocks are not in accord with statistics amassed on soil fragments and glasses. The term 'pristine' is taken to mean rocks with primary compositions (albeit not necessarily textures) produced by lunar endogenous igneous processes. Melt rocks and crystalline matrix breccias produced by impact processes are excluded. A petrographic synonym for pristine would be 'unremelted, monomict'. It is found that anorthositic norites and noritic anorthosites were rare as primary nonmare rocks. Mechanical mixing appears to have been the dominant petrogenetic process on the highlands.

Micron Scale Mapping and Depth Profiling of Organic Compounds in Geologic Material: Femtosecond - Laser Desorption Laser Postionization - Mass Spectrometry (fs-LDPI-MS)

NASA Astrophysics Data System (ADS)

Pasterski, M. J.; Barry, G. E.; Hanley, L.; Kenig, F. P. H.

2017-12-01

One of the major challenges within the field of organic geochemistry is to determine whether an observed biomarker signature is indigenous (emplaced during sedimentation), non-indigenous (emplaced after sedimentation) or contaminant (incorporated during sampling, storage or analysis). The challenge of determining the mode of emplacement of an observed biomarker signature is accentuated in analyses of Precambrian samples, and may be an issue upon Mars sample return. Current geochemical techniques (e.g. gas chromatography-mass spectrometry, GC-MS, GC×GC-MS) can determine the composition and structure of the organic constituents of a sample. However, the preparatory steps necessary prior to GC-MS analysis (sample crushing, solvent extraction) make it impossible to determine the precise spatial distribution of organic molecules within rocks and sediments. Here, we will present data from the first set of micron (2-5 μm width × 8 μm depth) resolution MS-images of organic compounds in geologic material. Fs-LDPI-MS was utilized to create MS-images of organic compounds in four samples: (1) an Antarctic igneous dike used as a sample blank; (2) a 93 million year-old (Ma) burrowed carbonate collected near Pueblo, CO; (3) a 164 Ma organic rich mudstone collected in central England; and (4) a 2680 Ma metasediment collected in Timmins, ON, Canada. Prior to this study, all samples had been analyzed via GC-MS to determine the bulk hydrocarbon composition. For this study, thick sections (70-100 μm thick) were prepared in-house using custom-designed clean preparation techniques. Petrographic maps of the thick sections were created to highlight geologic features such as burrows (sample 2), particulate organic matter (sample 3) and hydrothermal veins (sample 4). Fs-LDPI-MS analysis was performed on the mapped thick sections. MS-images of targeted organic compounds were created, and the MS-images were overlain with the petrographic maps to determine the spatial distribution of the organic compounds relative to host rock features. We were able to use the spatial distribution of the targeted organic compounds to unambiguously characterize them as either indigenous, non-indigenous or contaminants. This technique is applicable to the analysis of both Precambrian samples and extraterrestrial material.

Thin Film Transistors On Plastic Substrates

DOEpatents

Carey, Paul G.; Smith, Patrick M.; Sigmon, Thomas W.; Aceves, Randy C.

2004-01-20

A process for formation of thin film transistors (TFTs) on plastic substrates replaces standard thin film transistor fabrication techniques, and uses sufficiently lower processing temperatures so that inexpensive plastic substrates may be used in place of standard glass, quartz, and silicon wafer-based substrates. The silicon based thin film transistor produced by the process includes a low temperature substrate incapable of withstanding sustained processing temperatures greater than about 250.degree. C., an insulating layer on the substrate, a layer of silicon on the insulating layer having sections of doped silicon, undoped silicon, and poly-silicon, a gate dielectric layer on the layer of silicon, a layer of gate metal on the dielectric layer, a layer of oxide on sections of the layer of silicon and the layer of gate metal, and metal contacts on sections of the layer of silicon and layer of gate metal defining source, gate, and drain contacts, and interconnects.

Thick crystalline films on foreign substrates

DOEpatents

Smith, Henry I.; Atwater, Harry A.; Geis, Michael W.

1986-01-01

To achieve a uniform texture, large crystalline grains or, in some cases, a single crystalline orientation in a thick (>1 .mu.m) film on a foreign substrate, the film is formed so as to be thin (<1 .mu.m) in a certain section. Zone-melting recrystallization is initiated in the thin section and then extended into the thick section. The method may employ planar constriction patterns of orientation filter patterns.

Thick crystalline films on foreign substrates

DOEpatents

Smith, H.I.; Atwater, H.A.; Geis, M.W.

1986-03-18

To achieve a uniform texture, large crystalline grains or, in some cases, a single crystalline orientation in a thick (>1 [mu]m) film on a foreign substrate, the film is formed so as to be thin (<1 [mu]m) in a certain section. Zone-melting recrystallization is initiated in the thin section and then extended into the thick section. The method may employ planar constriction patterns of orientation filter patterns. 2 figs.

Properties, origin and nomenclature of rodlets of the inertinite maceral group in coals of the central Appalachian basin, U.S.A.

USGS Publications Warehouse

Lyons, P.C.; Finkelman, R.B.; Thompson, C.L.; Brown, F.W.; Hatcher, P.G.

1982-01-01

Resin rodlets, sclerenchyma strands and woody splinters, which are collectively called rodlets, were studied by chemical, optical petrographic, and scanning-electron microscopic (SEM) techniques. A study was made of such rodlets from the bituminous coal beds of the central Appalachian basin (Pennsylvanian; Upper Carboniferous) of the United States. Comparisons were made with rodlets from coal beds of the Illinois basin, the Southern Anthracite Field of Pennsylvania, the St. Rose coal field of Nova Scotia, and European and other coal fields. In order to determine their physical and chemical properties, a detailed study was made of the rodlets from the Pomeroy coal bed (high volatile A bituminous coal; Monongahela Formation; Upper Pennsylvanian) of Kanawha County, West Virginia. The origin of the rodlets was determined by a comparative analysis of a medullosan (seed fern) stem from the Herrin (No. 6) coal bed (high volatile C bituminous coal; Carbondale Formation) from Washington County, Illinois. Rodlets are commonly concentrated in fusain or carbominerite layers or lenses in bituminous coal beds of the central Appalachian basin. Most of the rodlets examined in our study were probably derived from medullosan seed ferns. The three types of rodlets are distinguished on the basis of cellularity, morphology and fracture. The resin rodlets studied by us are noncellular and appear to be similar in properties and origin to those found in coal beds of the Middle and Upper Pennsylvanian of the Illinois basin. The resin rodlets extracted from the Pomeroy coal bed exhibit high relief and high reflectance when polished and viewed in reflected light; they are opaque in transmitted light. In cross section, the resin rodlets are oval to round and have diameters ranging from 60 to 450 ??m. Many are solid, but some have vesicles, canals or cavities, which are commonly filled with clay, probably kaolinite. Typically, they have distinct fracture patterns ("kerfs") in longitudinal and cross sections and many are characterized by dense (probably oxidized) rims. The orientation and amounts of void space and mineralization of resin rodlets in coal have resulted in much confusion in their recognition and classification. The resin rodlets are petrographically recognized as sclerotinites of the inertinite maceral group. We here propose that resin rodlets be assigned to the maceral variety of sclerotinites termed "resino-sclerotinite" because of their presumable resinous origin. Other investigators have confused some fusinitized resin rodlets with fungal masses, which have different morphological properties and which probably have different chemical properties. We here propose that such fungal masses be assigned to the maceral variety of sclerotinites termed "fungo-sclerotinite.". The sclerenchyma strands examined in our study are cellular, thick-walled, and crescent-shaped in cross section. They exhibit high reflectance and high relief and belong to semifusinite and fusinite of the inertinite maceral group. Sclerenchyma strands are commonly associated with resin canals in Medullosa and related seed-fern genera, which are common in coal balls of the Illinois basin. We here propose adoption of the maceral varietal terms "sclerenchymo-fusinite" and "sclerenchymo-semifusinite" for these bodies. The woody splinters in the Pomeroy coal bed are cellular and thin-walled and have scattered pits as much as a few microns in diameter. They are dark brown to black in transmitted light and commonly have a lower reflectance than the resino-sclerotinite and sclerenchymo-fusinite of the Pomeroy coal. The woody splinters belong to semifusinite and fusinite of the inertinite maceral group. The maceral varietal terms "xylemo-semifusinite" and "xylemo-fusinite" are here proposed for these bodies. Elemental chemical data for the resin rodlets of the Pomeroy coal bed of the central Appalachian basin indicate that resin rodlets have significantly lower atomic H/C and O/C ratio

Modal petrology of six soils from Apollo 16 double drive tube core 64002

NASA Technical Reports Server (NTRS)

Houck, K. J.

1982-01-01

Petrographic data form six size fractions for six samples of Apollo 16 drive tube section 64002 show source rocks similar to those of core 60009. Analysis of modal data from the 64002 core show that the upper three and lowest core soils are mature and have similar maturation histories, while the two middle soils are submature and have histories that are similar to each other but unlike those from the aforementioned soils. In all of these soils, mixing has dominated over reworking, and appears to involve two mature soils distinguished by differing source rocks and an immature, plagioclase-rich soil which is correlated with larger clasts of chalky, friable breccia. These breccias and the plagioclase-rich soil are tentatively associated with the Descartes Formation.

Carbon analyses of IDP's sectioned in sulfur and supported on beryllium films

NASA Technical Reports Server (NTRS)

Bradley, J. P.; Keller, L.; Thomas, K. L.; Vanderwood, T. B.; Brownlee, D. E.

1993-01-01

Carbon is the only major element in interplanetary dust whose abundance, distribution and chemical state are not well understood. Information about carbon could clarify the relationship between the various classes of IDP's, conventional meteorites, and sources (e.g., comets vs. asteroids). To date, the most reliable estimates of C abundance in Interplanetary Dust Particles (IDP's) have been obtained by analyzing particles on thick-flat Be substrates using thin-window energy-dispersive spectroscopy in the SEM. These estimates of C abundance are valid only if C is homogeneously distributed, because detected C x-rays originate from the outer 0.1 micrometers of the particle. An alternative and potentially more accurate method of measuring C abundances is to analyze multiple thin sections (each less than 0.1 less than 0.1 micrometers thick) of IDP's. These efforts however, have been stymied because of a lack of a suitable non-carbonaceous embedding medium and the availability of C-free conductive substrates. We have embedded and thin-sectioned IDP's in glassy sulfur, and transferred the thin sections to Be support films approximately 25 nm thick. The sections were then analyzed in a 200 KeV analytical TEM. S sublimes rapidly under vacuum in the TEM, leaving non-embedded sections supported on Be. Apart from quantitative C (and O) analyses, S sectioning dramatically expands the range of analytical measurements that can be performed on a single IDP.

Color Video Petrography.

ERIC Educational Resources Information Center

Nagle, Frederick

1981-01-01

Describes the production and use of color videocassettes with an inexpensive, conventional TV camera and an ordinary petrographic microscope. The videocassettes are used in optical mineralogy and petrology courses. (Author/WB)

Catalog of lunar mare basalts greater than 40 grams. Part 1: Major and trace chemistry, with megascopic descriptions and rock and thin section photographs

NASA Technical Reports Server (NTRS)

Lofgren, G. E.; Lofgren, E. M.

1981-01-01

Megascopic descriptions of 133 basaltic rocks returned from the Moon are presented along with photographs of each rock and its thin section, if available. The major and trace element chemistry of each is included wherever possible.

Pipe support for use in a nuclear system

DOEpatents

Pollono, Louis P.; Mello, Raymond M.

1977-01-01

A pipe support for high temperature, thin-walled vertical piping runs used in a nuclear system. A cylindrical pipe transition member, having the same inside diameter as the thin-walled piping, replaces a portion of the piping where support is desired. The outside diameter of the pipe transition member varies axially along its vertical dimension. For a section of the axial length adjacent the upper and lower terminations of the pipe transition member, the outside diameter is the same as the outside diameter of the thin-walled piping to which it is affixed. Intermediate of the termination sections, the outside diameter increases from the top of the member to the bottom. Adjacent the lower termination section, the diameter abruptly becomes the same as the piping. Thus, the cylindrical transition member is formed to have a generally triangular shaped cross-section along the axial dimension. Load-bearing insulation is installed next to the periphery of the member and is kept in place by an outer ring clamp. The outer ring clamp is connected to pipe hangers, which provide the desired support for the vertical thin-walled piping runs.

Thin oblique airfoils at supersonic speed

NASA Technical Reports Server (NTRS)

Jone, Robert T

1946-01-01

The well-known methods of thin-airfoil theory have been extended to oblique or sweptback airfoils of finite aspect ratio moving at supersonic speeds. The cases considered thus far are symmetrical airfoils at zero lift having plan forms bounded by straight lines. Because of the conical form of the elementary flow fields, the results are comparable in simplicity to the results of the two-dimensional thin-airfoil theory for subsonic speeds. In the case of untapered airfoils swept back behind the Mach cone the pressure distribution at the center section is similar to that given by the Ackeret theory for a straight airfoil. With increasing distance from the center section the distribution approaches the form given by the subsonic-flow theory. The pressure drag is concentrated chiefly at the center section and for long wings a slight negative drag may appear on outboard sections. (author)

Localized thin-section CT with radiomics feature extraction and machine learning to classify early-detected pulmonary nodules from lung cancer screening

NASA Astrophysics Data System (ADS)

Tu, Shu-Ju; Wang, Chih-Wei; Pan, Kuang-Tse; Wu, Yi-Cheng; Wu, Chen-Te

2018-03-01

Lung cancer screening aims to detect small pulmonary nodules and decrease the mortality rate of those affected. However, studies from large-scale clinical trials of lung cancer screening have shown that the false-positive rate is high and positive predictive value is low. To address these problems, a technical approach is greatly needed for accurate malignancy differentiation among these early-detected nodules. We studied the clinical feasibility of an additional protocol of localized thin-section CT for further assessment on recalled patients from lung cancer screening tests. Our approach of localized thin-section CT was integrated with radiomics features extraction and machine learning classification which was supervised by pathological diagnosis. Localized thin-section CT images of 122 nodules were retrospectively reviewed and 374 radiomics features were extracted. In this study, 48 nodules were benign and 74 malignant. There were nine patients with multiple nodules and four with synchronous multiple malignant nodules. Different machine learning classifiers with a stratified ten-fold cross-validation were used and repeated 100 times to evaluate classification accuracy. Of the image features extracted from the thin-section CT images, 238 (64%) were useful in differentiating between benign and malignant nodules. These useful features include CT density (p  =  0.002 518), sigma (p  =  0.002 781), uniformity (p  =  0.032 41), and entropy (p  =  0.006 685). The highest classification accuracy was 79% by the logistic classifier. The performance metrics of this logistic classification model was 0.80 for the positive predictive value, 0.36 for the false-positive rate, and 0.80 for the area under the receiver operating characteristic curve. Our approach of direct risk classification supervised by the pathological diagnosis with localized thin-section CT and radiomics feature extraction may support clinical physicians in determining truly malignant nodules and therefore reduce problems in lung cancer screening.

Localized thin-section CT with radiomics feature extraction and machine learning to classify early-detected pulmonary nodules from lung cancer screening.

PubMed

Tu, Shu-Ju; Wang, Chih-Wei; Pan, Kuang-Tse; Wu, Yi-Cheng; Wu, Chen-Te

2018-03-14

Lung cancer screening aims to detect small pulmonary nodules and decrease the mortality rate of those affected. However, studies from large-scale clinical trials of lung cancer screening have shown that the false-positive rate is high and positive predictive value is low. To address these problems, a technical approach is greatly needed for accurate malignancy differentiation among these early-detected nodules. We studied the clinical feasibility of an additional protocol of localized thin-section CT for further assessment on recalled patients from lung cancer screening tests. Our approach of localized thin-section CT was integrated with radiomics features extraction and machine learning classification which was supervised by pathological diagnosis. Localized thin-section CT images of 122 nodules were retrospectively reviewed and 374 radiomics features were extracted. In this study, 48 nodules were benign and 74 malignant. There were nine patients with multiple nodules and four with synchronous multiple malignant nodules. Different machine learning classifiers with a stratified ten-fold cross-validation were used and repeated 100 times to evaluate classification accuracy. Of the image features extracted from the thin-section CT images, 238 (64%) were useful in differentiating between benign and malignant nodules. These useful features include CT density (p  =  0.002 518), sigma (p  =  0.002 781), uniformity (p  =  0.032 41), and entropy (p  =  0.006 685). The highest classification accuracy was 79% by the logistic classifier. The performance metrics of this logistic classification model was 0.80 for the positive predictive value, 0.36 for the false-positive rate, and 0.80 for the area under the receiver operating characteristic curve. Our approach of direct risk classification supervised by the pathological diagnosis with localized thin-section CT and radiomics feature extraction may support clinical physicians in determining truly malignant nodules and therefore reduce problems in lung cancer screening.

Fluid Dynamic and Stability Analysis of a Thin Liquid Sheet

NASA Technical Reports Server (NTRS)

McMaster, Matthew S.

1992-01-01

Interest in thin sheet flows has recently been renewed due to their potential application in space radiators. Theoretical and experimental studies of the fluid dynamics and stability of thin liquid sheet flows have been carried out in this thesis. A computer program was developed to determine the cross-sectional shape of the edge cylinder given the cross-sectional area of the edge cylinder. A stability analysis was performed on a non-planer liquid sheet. A study was conducted to determine the effects of air resistance on the sheet.

Stratigraphic variation in petrographic composition of Nanushuk Group sandstones at Slope Mountain, North Slope, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998

USGS Publications Warehouse

Johnsson, Mark J.; Sokol, Nikolas K.

2000-01-01

Fluvial, deltaic, and marine sediments of the Nanushuk Group (Albian to Cenomanian), North Slope, Alaska, record Early Cretaceous orogenic events in the Brooks Range to the south. The 1,060-m section at Slope Mountain is part of the Lower Cretaceous Umiat Delta, shed from the Endicott and De Long Mountains subterranes in the central Brooks Range. These sandstones are litharenites dominated by metasedimentary lithic fragments. Subtle and previously unrecognized stratigraphic variations in composition (up-section increases in metasedimentary lithic fragments, volcanic lithic fragments, and quartz interpreted to be of metamorphic origin) reflect a combination of facies migration and changes in provenance associated with unroofing of the ancestral Brooks Range. We recognize stratigraphic variation in sandstone composition at Slope Mountain whereas previous workers have not, probably because of our use of finely subdivided point-counting categories. The source of the volcanic lithic fragments in the Nanushuk Group remains enigmatic; the most likely candidate is a now-eroded volcanic arc, perhaps a volcanic superstructure to granitic rocks of the Ruby terrane to the south.

Incorporating Problem-Based Learning Into A Petrology Course Through A Research Project In The Local Northern Sierra Nevada

NASA Astrophysics Data System (ADS)

Aird, H. M.

2016-12-01

A research project into the local petrology was integrated into the Spring 2016 Petrology and Optical Mineralogy course at California State University, Chico. This is a required majors course, typically taken during spring of the junior year, with an enrollment of 10-20 students. Since the labs for this course have a strong focus on petrography, a research project was introduced to give students experience in using a multi-faceted approach to investigate a problem. In many cases, this is their first taste of research. During the first week of the Spring 2016 class, students were introduced to the research question: In the broader context of Californian tectonic history, are the Bucks Lake and Grizzly plutons of the northern Sierra Nevada petrogenetically related? With faculty guidance over the course of the semester, students carried out fieldwork and sampling, lithologic description, selection of the best samples for further analysis, thin section production, petrographic description, and analysis and interpretation of published geochemical data. Research activities were strategically scheduled within the course framework such that students were academically prepared to carry out each task. Each student was responsible for generating all the data for one sample, and data were then collated as a class, so students wrote their individual final reports using all the data collected by the class. Careful scaffolding of writing assignments throughout the semester guided students through the preparation of an academic-style scientific report, while allowing for repeated feedback on their writing style and content. In mid-May, the class presented a group poster at the College of Natural Sciences annual poster symposium, and were awarded `Best Student Class Project' by the judges. Anecdotal student feedback indicated they highly valued the research experience and some were inspired to pursue individual undergraduate research projects under faculty supervision.

Post-deformational relocation of mica grains in calcite-dolomite marbles identified by cathodoluminescence microscopy

NASA Astrophysics Data System (ADS)

Kuehn, Rebecca; Duschl, Florian; Leiss, Bernd

2017-04-01

Hot-cathodoluminescence-microscopy (CL) reveals micas which are rotated or shifted within a calcite fabric from a foliation parallel to a random orientation. This feature has been recognized in calcite-dolomite marble samples from the locations Hammerunterwiesenthal, Erzgebirge, Germany and the Alpi Apuane, Italy. As obtained from petrographic thin section analysis, the micas either moved totally within a single calcite grain or from a grain boundary position, and then the calcite grain growth was dragged with the movement of the mica grain. In the moved-through grain, features like fluid-inclusions, twins or cleavage faces are erased and a new, clear calcite phase developed. This indicates dissolution-precipitation as process which led to the new calcite phase. As former deformation features are erased it can be assumed that the mica relocation is a fluid-driven, post-deformational equilibration process. In CL the new calcite mineral phase shows a zonation indicating a polycyclic process. Calcite CL gradually changes from a very dark purple, exactly as the surrounding grains, to a bright orange CL and supports the idea of fluid-induced deformation relocation. We suppose a specific lattice relationship between mica and calcite as initial driving factor for mica relocation. This recrystallization mechanism is probably supported by fluids - either from an external source or developed during retrograde metamorphosis fluid inclusion studies shall identify formation temperatures and origin of involved fluids and thereby clarify the timing of the post-deformational mica rotation. EBSD analysis of involved calcite and mica grains shall reveal a possible systematic relationship between the orientation of the hosting grains, the orientation of the mica and the final position of the mica. It will be interesting to learn in the future, if this kind of calcite-mica microstructure is a general phenomenon and how it can contribute to the understanding of fabric development.

Stratigraphic evolution of the Late Jurassic Hanifa Formation along the Tuwaiq Escarpment, Saudi Arabia: Evidence for a carbonate ramp system

NASA Astrophysics Data System (ADS)

Fallatah, Mohammed I.; Kerans, Charles

2018-01-01

A sequence stratigraphic framework of the Late Jurassic (Oxfordian) Hanifa Formation at its exposure in Central Arabia is presented for the first time. This study offers the first high-resolution stratigraphic framework of the Hanifa along the Tuwaiq Escarpment by measuring 15 sections ( 770 m total thickness) over an oblique-to-dip distance of 260 km and collecting 295 samples for petrographic analysis. On the basis of these data, the Hanifa Formation can be subdivided into eight facies; 1) tabular cross-bedded quartz-peloidal-skeletal grainstone, 2) cross-bedded skeletal-peloidal grainstone, 3) bioturbated foraminiferal wackestone/mud-dominated packstone, 4) oncolitic rudstone, 5) stromatoporoid-coral biostrome/bioherm, 6) peloidal/composite-grain grain-dominated packstone/grainstone, 7) bioturbated spiculitic wackestone/mud-dominated packstone, and 8) thinly-bedded argillaceous mudstone/wackestone. The vertical and lateral distributions of these facies along the exposure define their sequence setting using the principals of sequence stratigraphy. By recognizing erosional surfaces, facies offset, and changes in facies proportions, five third-order sequences, with an average duration of 1.1 Myr, are interpreted for the Hanifa Formation. The correlation of the sequences across the study area shows that only four sequences are preserved in the north where shallow-water deposits are well-developed. Facies trends within these sequences are further illustrated in depositional models representing the highstand systems tracts (HST) and the transgressive systems tracts (TST) of the Hanifa Formation. These proposed models represent depositional settings of a carbonate ramp with normal open-marine conditions. The HST depositional model is characterized by a high-energy shoreline and depicts the presence of an offshore, structurally controlled skeletal-peloidal shoal body described here for the first time at the Hanifa exposure in the Hozwa area. This work provides a predictive framework and outcrop analog for applications in hydrocarbon exploration and development. Furthermore, a basinal setting predicted to the south of the study area is a potential site for unconventional plays.

Ultrastructural and geochemical characterization of Archean-Paleoproterozoic graphite particles: implications for recognizing traces of life in highly metamorphosed rocks.

PubMed

Schiffbauer, James D; Yin, Leiming; Bodnar, Robert J; Kaufman, Alan J; Meng, Fanwei; Hu, Jie; Shen, Bing; Yuan, Xunlai; Bao, Huiming; Xiao, Shuhai

2007-08-01

Abundant graphite particles occur in amphibolite-grade quartzite of the Archean-Paleoproterozoic Wutai Metamorphic Complex in the Wutaishan area of North China. Petrographic thin section observations suggest that the graphite particles occur within and between quartzite clasts and are heterogeneous in origin. Using HF maceration techniques, the Wutai graphite particles were extracted for further investigation. Laser Raman spectroscopic analysis of a population of extracted graphite discs indicated that they experienced a maximum metamorphic temperature of 513 +/- 50 degrees C, which is consistent with the metamorphic grade of the host rock and supports their indigenicity. Scanning and transmission electron microscopy revealed that the particles bear morphological features (such as hexagonal sheets of graphite crystals) related to metamorphism and crystal growth, but a small fraction of them (graphite discs) are characterized by a circular morphology, distinct marginal concentric folds, surficial wrinkles, and complex nanostructures. Ion microprobe analysis of individual graphite discs showed that their carbon isotope compositions range from -7.4 per thousand to -35.9 per thousand V-PDB (Vienna Pee Dee Belemnite), with an average of -20.3 per thousand, which is comparable to bulk analysis of extracted carbonaceous material. The range of their size, ultrastructures, and isotopic signatures suggests that the morphology and geochemistry of the Wutai graphite discs were overprinted by metamorphism and their ultimate carbon source probably had diverse origins that included abiotic processes. We considered both biotic and abiotic origins of the carbon source and graphite disc morphologies and cannot falsify the possibility that some circular graphite discs characterized by marginal folds and surficial wrinkles represent deflated, compressed, and subsequently graphitized organic-walled vesicles. Together with reports by other authors of acanthomorphic acritarchs from greenschist-amphibolite-grade metamorphic rocks, this study suggests that it is worthwhile to examine carbonaceous materials preserved in highly metamorphosed rocks for possible evidence of ancient life.

Characterization of alteration textures in Cretaceous oceanic crust (pillow lava) from the N-Atlantic (DSDP Hole 418A) by spatially-resolved spectroscopy

NASA Astrophysics Data System (ADS)

Fliegel, Daniel; Knowles, Emily; Wirth, Richard; Templeton, Alexis; Staudigel, Hubert; Muehlenbachs, Karlis; Furnes, Harald

2012-11-01

The habit, mineralogy, crystallography, and Fe speciation of tubular and granular alteration textures in basaltic glass recovered from DSDP Hole 418A, which have previously been associated with biologically mediated alteration, were investigated using an integrated suite of microscopic and spectroscopic approaches in order to shine light on their formation and mineralization history. Two different analytical approaches were used: (1) micro scale investigations with conventional petrographic optical microcopy and microscale X-ray fluorescence mapping and X-ray absorption spectroscopy, and (2) nano scale analyses with FIB (focused ion beam milling) to prepare cross-sections for TEM (transmission electron microscopy), EELS (electron energy loss spectroscopy), and STXM (scanning transmission electron microscopy) analyses. The integrated data show that tubular and granular textures are similar in chemical, mineralogical and structural habit. Both granular and tubular alteration textures show a marked transition from ferrous iron in the glass matrix to ferric iron in the textures. Granular and tubular textures are filled with sheet silicates of similar chemistry, and both exhibit thin amorphous alteration rims ∼10-20 nm wide. The alteration rims are typically depleted in Ca and Fe. Ca is enriched at the contact between the secondary mineralization and the alteration rims, whereas Fe is enriched throughout the alteration features and is mainly present as FeIII in contrast to FeII in the host glass. Carbon is enriched only in a few areas, and could possibly be of organic origin but is not bound in carbonate. The mineralization of the features follows the sequence: dissolution of the glass; formation of a leached amorphous rim; mineralizing the cavities by smectide type clays and subsequently congruent growing of the texture diameter by diffusing of the elements through the alteration layer. None of the features could be linked solely to a biogenic origin and hence the biogenicity of the textures can neither be refuted nor supported by this micro- and nano-scale data set.

Facies analysis of tuffaceous volcaniclastics and felsic volcanics of Tadpatri Formation, Cuddapah basin, Andhra Pradesh, India

NASA Astrophysics Data System (ADS)

Goswami, Sukanta; Dey, Sukanta

2018-05-01

The felsic volcanics, tuff and volcaniclastic rocks within the Tadpatri Formation of Proterozoic Cuddapah basin are not extensively studied so far. It is necessary to evaluate the extrusive environment of felsic lavas with associated ash fall tuffs and define the resedimented volcaniclastic components. The spatial and temporal bimodal association were addressed, but geochemical and petrographic studies of mafic volcanics are paid more attention so far. The limited exposures of eroded felsic volcanics and tuffaceous volcaniclastic components in this terrain are highly altered and that is the challenge of the present facies analysis. Based on field observation and mapping of different lithounits a number of facies are categorized. Unbiased lithogeochemical sampling have provided major and selective trace element data to characterize facies types. Thin-section studies are also carried out to interpret different syn- and post- volcanic features. The facies analysis are used to prepare a representative facies model to visualize the entire phenomenon with reference to the basin evolution. Different devitrification features and other textural as well as structural attributes typical of flow, surge and ash fall deposits are manifested in the middle, lower and upper stratigraphic levels. Spatial and temporal correlation of lithologs are also supportive of bimodal volcanism. Felsic and mafic lavas are interpreted to have erupted through the N-S trending rift-associated fissures due to lithospheric stretching during late Palaeoproterozoic. It is also established from the facies model that the volcaniclastics were deposited in the deeper part of the basin in the east. The rifting and associated pressure release must have provided suitable condition of decompression melting at shallow depth with high geothermal gradient and this partial melting of mantle derived material at lower crust must have produced mafic magmas. Such upwelling into cold crust also caused partial heat transfer and associated melting of the surrounding shallow crustal rocks to generate felsic magmas.

Hailar crater - A possible impact structure in Inner Mongolia, China

NASA Astrophysics Data System (ADS)

Xiao, Zhiyong; Chen, Zhaoxu; Pu, Jiang; Xiao, Xiao; Wang, Yichen; Huang, Jun

2018-04-01

Hailar crater, a probable impact structure, is a circular depression about 300 m diameter in Inner Mongolia, northeast China. With broad elevated rims, the present rim-to-floor depth is 8-20 m. Regional geological background and geomorphological comparison suggest that this feature is likely not formed by surface processes such as salt diapir, karst, aeolian, glacial, or volcanic activity. Its unique occurrence in this region and well-preserved morphology are most consistent with it being a Cenozoic impact crater. Two field expeditions in 2016 and 2017 investigated the origin of this structure, recognizing that (1) no additional craters were identified around Hailar crater in the centimeter-scale digital topography models that were constructed using a drone imaging system and stereo photogrammetry; (2) no bedrock exposures are visible within or adjacent to the crater because of thick regolith coverage, and only small pieces of angular unconsolidated rocks are present on the crater wall and the gently-sloped crater rim, suggesting recent energetic formation of the crater; (3) most samples collected from the crater have identical lithology and petrographic characteristics with the background terrain, but some crater samples contain more abundant clasts and silicate hydrothermal veins, indicating that rocks from depths have been exposed by the crater; (4) no shock metamorphic features were found in the samples after thin section examinations; and (5) a systematic sample survey and iron detector scan within and outside of the crater found no iron-rich meteorites larger than 2 cm in size in a depth of 30 cm. Although no conclusive evidence for an impact origin is found yet, Hailar crater was most likely formed by an impact based on its unique occurrence and comparative geomorphologic study. We suggest that drilling in the crater center is required to verify the impact origin, where hypothesized melt-bearing impactites may be encountered.

Thermal maturity and organic composition of Pennsylvanian coals and carbonaceous shales, north-central Texas: Implications for coalbed gas potential

USGS Publications Warehouse

Hackley, P.C.; Guevara, E.H.; Hentz, T.F.; Hook, R.W.

2009-01-01

Thermal maturity was determined for about 120 core, cuttings, and outcrop samples to investigate the potential for coalbed gas resources in Pennsylvanian strata of north-central Texas. Shallow (< 600??m; 2000??ft) coal and carbonaceous shale cuttings samples from the Middle-Upper Pennsylvanian Strawn, Canyon, and Cisco Groups in Archer and Young Counties on the Eastern Shelf of the Midland basin (northwest and downdip from the outcrop) yielded mean random vitrinite reflectance (Ro) values between about 0.4 and 0.8%. This range of Ro values indicates rank from subbituminous C to high volatile A bituminous in the shallow subsurface, which may be sufficient for early thermogenic gas generation. Near-surface (< 100??m; 300??ft) core and outcrop samples of coal from areas of historical underground coal mining in the region yielded similar Ro values of 0.5 to 0.8%. Carbonaceous shale core samples of Lower Pennsylvanian strata (lower Atoka Group) from two deeper wells (samples from ~ 1650??m; 5400??ft) in Jack and western Wise Counties in the western part of the Fort Worth basin yielded higher Ro values of about 1.0%. Pyrolysis and petrographic data for the lower Atoka samples indicate mixed Type II/Type III organic matter, suggesting generated hydrocarbons may be both gas- and oil-prone. In all other samples, organic material is dominated by Type III organic matter (vitrinite), indicating that generated hydrocarbons should be gas-prone. Individual coal beds are thin at outcrop (< 1??m; 3.3??ft), laterally discontinuous, and moderately high in ash yield and sulfur content. A possible analog for coalbed gas potential in the Pennsylvanian section of north-central Texas occurs on the northeast Oklahoma shelf and in the Cherokee basin of southeastern Kansas, where contemporaneous gas-producing coal beds are similar in thickness, quality, and rank.

Bioerosion by euendoliths decreases in phosphate-enriched skeletons of living corals

NASA Astrophysics Data System (ADS)

Godinot, C.; Tribollet, A.; Grover, R.; Ferrier-Pagès, C.

2012-03-01

While the role of microboring organisms, or euendoliths, is relatively well known in dead coral skeletons, their function in live corals remains poorly understood. They are suggested to behave like ectosymbionts or parasites, impacting their host health. However, the species composition of microboring communities, their abundance and dynamics in live corals under various environmental conditions have never been explored. Here, the effect of phosphate enrichment on boring microorganisms in live corals was tested for the first time. S. pistillata nubbins were exposed to 3 different treatments (phosphate enrichments of 0, 0.5 and 2.5 μmol l-1) during 15 weeks. After 15 weeks of phosphate enrichment, petrographic thin sections were prepared for observation with light microscopy, and additional samples were examined with scanning electron microscopy (SEM). Euendoliths comprised mainly autotrophic Ostreobium sp. filaments. Rare filaments of heterotrophic fungi were also observed. Filaments were densely distributed in the central part of nubbins, and less abundant towards the apex. Unexpectedly, there was a visible reduction of filaments abundance in the most recently-calcified apical part of phosphate-enriched nubbins. The overall abundance of euendoliths significantly decreased, from 9.12 ± 1.09% of the skeletal surface area in unenriched corals, to 5.81 ± 0.77% and 5.27 ± 0.34% in 0.5 and 2.5 μmol l-1-phosphate enriched corals respectively. SEM observations confirmed this decrease. Recent studies have shown that phosphate enrichment increases coral skeletal growth and metabolic rates, while it decreases skeletal density and resilience to mechanical stress. We thus hypothesize that increased skeletal growth in the presence of phosphate enrichment occurred too fast for an effective euendolith colonization. They could not keep up with coral growth, so they became diluted in the apex areas as nubbins grew with phosphate enrichment. The possible advantages and downsides of the reduction of euendoliths associated with phosphate eutrophication in live corals are discussed in this article.

Unshocked Equilibrated H Chondrites: A Common Low-Temperature Record from Fe-Mg Ordering in Orthopyroxene

NASA Astrophysics Data System (ADS)

Folco, L.; Mellini, M.; Pillinger, C. T.

1995-09-01

The study of the thermal metamorphism of ordinary chondrites through geothermometers can provide significant constraints on the parent body thermal models which remain controversial. We report here results from Fe-Mg ordering closure temperatures (Tc) of orthopyroxenes from eight unshocked equilibrated H-chondrites obtained by means of single crystal X-ray diffraction. The method is based on the fact that cation partitioning in orthopyroxene is sensitive to temperature [1], and makes use of the experimental calibration by Molin et al. [2]. The goal of the investigation is to check how petrographic types relate to cation ordering thermal records. Results: The orthopyroxenes show a very similar degree of Fe-Mg ordering (see Table 1.). The Tc's cluster within the 384+/-48 to 480+/-28 degrees C interval, and show no correlation with petrographic type. The lack of a correlation does not mean that the distribution is random, rather, it appears to be controlled in individual samples by the degree of equilibration. In fact, the higher the petrographic type, the more coherent the results of the grains from individual chondrites. The spread of Tc's in the least equilibrated chondrites could be either a memory of heterogeneous pre-metamorphic records related to individual chondrule histories, or an artefact due to crystal defects. Therefore (1) the thermal records, inferred from the Fe-Mg ordering, are nearly the same for all the equilibrated H-chondrites; (2) the most equilibrated chondrites record distinct Tc values within the larger common Tc range; (3) the spread of Tc in H4's maybe indicative of disequilibrium and merits further study. The closure temperature conveys information on the cooling rate close to its value, regardless of the temperature regimes when the ordering process started. Extrapolation to high temperatures can be made only if the cooling path is constrained. Since we have no data to establish the temperature when ordering began and to decide whether the cooling was linear, we have not attempted quantitative estimates of cooling rates. However we can say that as equilibrated H-chondrites carry similar Tc records, they cooled at similar rates through 380-480 degrees C. However, the k(sub)D's (i.e., the intracrystalline Fe-Mg distribution coefficient) range 0.029 to 0.054, suggesting that H-chondrites cooled in petrogenetic environments intermediate between those of volcanic [3] and granulitic rocks [3,4]. Conclusion: Our results provide the following constraints: (1) Equilibrated H-chondrites, regardless the petrographic type, were located in petrogenetic environments characterized by similar temperature-time conditions when cooling through 380-480 degrees C, and, in terms of terrestrial environments, intermediate between those of volcanic and granulitic facies. (2) Different petrographic types reflect distinct metamorphic thermal regimes. Thus, to account for constraint (1), petrographic type was determined at temperatures above the 380-480 degrees C interval. This implies that equilibrated H-chondrites were placed in different geological environments characterized by distinct temperature-time regimes when still above this temperature range. In the case of the least equilibrated chondrites, for which the two events could coincide. Acknowledgments: We thank EUROMET for providing us with the Frontier Mt. samples, and PNRA for supporting this study. References: [1] Saxena S. K. and Dal Negro A. (1983) Bull. Min ral., 106, 443-449. [2] Molin G. M. et al. (1991) EPSL, 105, 260-265. [3] Bertolo S. and Nimis P. (1993) EJM, 5, 707-719. [4] Tribaudino M. and Talarico F. (1992) EJM, 4, 453-463.

[Normal and pathological elastic tissue under the electron microscope on thin and ultrathin sections (author's transl)].

PubMed

Adnet, J J; Pinteaux, A; Pousse, G; Caulet, T

1976-04-01

Three simple methods (adapted from optical techniques) for normal and pathological elastic tissue caracterisation in electron microscopy on thin and ultrathin sections are proposed. Two of these methods (orcein and fuchsin resorcin) seem to have a specificity for arterial and breast cancer elastic tissue. Weigert's method gives the best contrast.

Internal-external flow integration for a thin ejector-flapped wing section

NASA Technical Reports Server (NTRS)

Woolard, H. W.

1979-01-01

Thin airfoil theories of an ejector flapped wing section are reviewed. The global matching of the external airfoil flow with the ejector internal flow and the overall ejector flapped wing section aerodynamic performance are examined. Mathematical models of the external and internal flows are presented. The delineation of the suction flow coefficient characteristics are discussed. The idealized lift performance of an ejector flapped wing relative to a jet augmented flapped wing are compared.

Ice crystal c-axis orientation and mean grain size measurements from the Dome Summit South ice core, Law Dome, East Antarctica

NASA Astrophysics Data System (ADS)

Treverrow, Adam; Jun, Li; Jacka, Tim H.

2016-06-01

We present measurements of crystal c-axis orientations and mean grain area from the Dome Summit South (DSS) ice core drilled on Law Dome, East Antarctica. All measurements were made on location at the borehole site during drilling operations. The data are from 185 individual thin sections obtained between a depth of 117 m below the surface and the bottom of the DSS core at a depth of 1196 m. The median number of c-axis orientations recorded in each thin section was 100, with values ranging from 5 through to 111 orientations. The data from all 185 thin sections are provided in a single comma-separated value (csv) formatted file which contains the c-axis orientations in polar coordinates, depth information for each core section from which the data were obtained, the mean grain area calculated for each thin section and other data related to the drilling site. The data set is also available as a MATLAB™ structure array. Additionally, the c-axis orientation data from each of the 185 thin sections are summarized graphically in figures containing a Schmidt diagram, histogram of c-axis colatitudes and rose plot of c-axis azimuths. All these data are referenced by doi:10.4225/15/5669050CC1B3B and are available free of charge at https://data.antarctica.gov.au.<

Anomalous Orthopyroxene Cell Volumes from Unshocked Equilibrated H Chondrites

NASA Astrophysics Data System (ADS)

Folco, L.; Mellini, M.; Pillinger, C. T.

1995-09-01

Thirteen orthopyroxenes were extracted from eight unshocked equilibrated H-chondrites representatives of the petrographic types 4 to 6 [1] for crystal-chemical analyses. Chemical compositions were determined through a WDS JEOL JX 8600 electron microprobe. Three to six spot analyses were run on each crystal and no significant chemical variation was detected. High quality single crystal X-ray diffraction data were obtained by a SIEMENS P4 diffractometer using MoK alpha radiation, and site occupancies by least squares structure refinements. Figure 1a shows a significant cell volume (Vc) increase with petrographic type, and a _1.5 Angstrom^3 spread within each petrographic type. In solid solutions, Vc is expected to mainly vary with the chemical composition: the higher the proportion of the large ions present, the larger the Vc. In particular, as shown by [2], Vc variations in orthopyroxenes are essentially linear with Fe/(Fe+Mg), and our data fall within this general trend. However, no such a correlation exists at the scale of our values (Fig.1b), rather, each petrographic type plots along a different roughly negative trend. Furthermore, as experimentally obtained by [3], the decrease of the Fe-Mg ordering between the M1 and M2 sites in orthopyroxenes (a temperature-time-dependent process), causes significant Vc increase due to the displacement of the large Fe2+ ions from the larger M2 to the smaller M1 sites. Again, in the Vc versus kD (i.e., the intracrystalline Fe-Mg distribution coefficient) diagram (Fig.1c), we observe no such a correlation. Contrary to the most immediate expectations, our data suggest that the net increase in Vc from H4 to H6 does not significantly depend upon chemical composition and degree of ordering, and demands that another as yet unidentified parameter accounts for the observed trends. Acknowledgments: We thank EUROMET for the Frontier Mt. samples, and PNRA for supporting this study. References: [1] Folco L. et al., this volume. [2] Sykes-Nord J. A. and Molin G. M. (1993) Am. Mineral., 78, 921-931. [3] Domeneghetti M. C. et al. (1985). Am. Mineral., 70, 987-995.

Metamorphism and aqueous alteration in low petrographic type ordinary chondrites

NASA Technical Reports Server (NTRS)

Xie, T.; Lipschutz, M. E.; Sears, D. W. G.; Guimon, R. K.; Jie, Lu; Benoit, P. H.; O'D. Alexander, C. M.; Wright, Ian; Pillinger, C.; Morse, A. D.;

Lunar Rocks: Available for Year of the Solar System Events

NASA Astrophysics Data System (ADS)

Allen, J. S.

2010-12-01

NASA is actively exploring the moon with our Lunar Reconnaissance Orbiter, the Grail Discovery Mission will launch next year, and each year there is an International Observe the Moon Night providing many events and lunar science focus opportunities to share rocks from the moon with students and the public. In our laboratories, we have Apollo rocks and soil from six different places on the moon, and their continued study provides incredibly valuable ground truth to complement space exploration missions. Extensive information and actual lunar samples are available for public display and education. The Johnson Space Center (JSC) has the unique responsibility to curate NASA's extraterrestrial samples from past and future missions. Curation includes documentation, preservation, preparation, and distribution of samples for research, education, and public outreach. The lunar rocks and soils continue to be studied intensively by scientists around the world. Descriptions of the samples, research results, thousands of photographs, and information on how to request research samples are on the JSC Curation website: http://curator.jsc.nasa.gov/ NASA is eager for scientists and the public to have access to these exciting Apollo samples through our various loan procedures. NASA provides a limited number of Moon rock samples for either short-term or long-term displays at museums, planetariums, expositions, and professional events that are open to the public. The JSC Public Affairs Office handles requests for such display samples. Requestors should apply in writing to Mr. Louis Parker, JSC Exhibits Manager. Mr. Parker will advise successful applicants regarding provisions for receipt, display, and return of the samples. All loans will be preceded by a signed loan agreement executed between NASA and the requestor's organization. Email address: louis.a.parker@nasa.gov Sets of twelve thin sections of Apollo lunar samples are available for short-term loan from JSC Curation. The thin sections may be use requested for college and university courses where petrographic microscopes are available for viewing. Requestors should contact Ms. Mary Luckey, Education Sample Curator. Email address: mary.k.luckey@nasa.gov NASA also loans sets of Moon rocks for use in classrooms, libraries, museums, and planetariums through the Lunar Sample Education Program. Lunar samples (three soils and three rocks) are encapsulated in a six-inch diameter clear plastic disk. A CD with PowerPoint presentations, analogue samples from Earth, a classroom activity guide, and additional printed material accompany the disks. Educators may qualify for the use of these disks by attending a content and security certification workshop sponsored by NASA's Aerospace Education Services Program (AESP). Contact Ms. Margaret Maher, AESP Director. Email address: mjm67@psu.edu NASA makes these precious samples available for the public and encourages the use of lunar rocks to highlight Year of the Solar System events. Surely these interesting specimens of another world will enhance the experience of all YSS participants so please take advantage of these lunar samples and borrow them for events and classes.

Obtaining Magnetic Properties of Meteorites Using Magnetic Scanner

NASA Astrophysics Data System (ADS)

Kletetschka, G.; Nabelek, L.; Mazanec, M.; Simon, K.; Hruba, J.

2015-12-01

Magnetic images of Murchison meteorite's and Chelyabinsk meteorite's thin section have been obtained from magnetic scanning system from Youngwood Science and Engineering (YSE) capable of resolving magnetic anomalies down to 10-3 mT range from about 0.3 mm distance between the probe and meteorite surface (resolution about 0.15 mm). Anomalies were produced repeatedly, each time after application of magnetic field pulse of varying amplitude and constant, normal or reversed, direction. This process resulted in both magnetizing and demagnetizing of the meteorite thin section, while keeping the magnetization vector in the plane of the thin section. Analysis of the magnetic data allows determination of coercivity of remanence (Bcr) for the magnetic sources in situ. Value of Bcr is critical for calculating magnetic forces applicable during missions to asteroids where gravity is compromised. Bcr was estimated by two methods. First method measured varying dipole magnetic field strength produced by each anomaly in the direction of magnetic pulses. Second method measured deflections of the dipole direction from the direction of magnetic pulses (Nabelek et al., 2015). Nabelek, L., Mazanec, M., Kdyr, S., and Kletetschka, G., 2015, Magnetic, in situ, mineral characterization of Chelyabinsk meteorite thin section: Meteoritics & Planetary Science.

Evaluation of consolidation in concrete pavements.

DOT National Transportation Integrated Search

1994-01-01

Petrographic examinations of specimens from two recently constructed concrete pavements suggested that complete consolidation of the concrete may not have been achieved. Consequently, a quantitative evaluation of the degree of consolidation in these ...

Method and system for constructing a rechargeable battery and battery structures formed with the method

DOEpatents

Hobson, David O.; Snyder, Jr., William B.

1995-01-01

A method and system for manufacturing a thin-film battery and a battery structure formed with the method utilizes a plurality of deposition stations at which thin battery component films are built up in sequence upon a web-like substrate as the substrate is automatically moved through the stations. At an initial station, cathode and anode current collector film sections are deposited upon the substrate, and at another station, a thin cathode film is deposited upon the substrate so to overlie part of the cathode current collector section. At another station, a thin electrolyte film is deposited upon so as to overlie the cathode film and part of the anode current collector film, at yet another station, a thin lithium film is deposited upon so as to overlie the electrolyte film and an additional part of the anode current collector film. Such a method accommodates the winding of a layup of battery components into a spiral configuration to provide a thin-film, high capacity battery and also accommodates the build up of thin film battery components onto a substrate surface having any of a number of shapes.

Photomosaics of the cathodoluminescence of 60 sections of meteorites and lunar samples

USGS Publications Warehouse

Akridge, D.G.; Akridge, J.M.C.; Batchelor, J.D.; Benoit, P.H.; Brewer, J.; DeHart, J.M.; Keck, B.D.; Jie, L.; Meier, A.; Penrose, M.; Schneider, D.M.; Sears, D.W.G.; Symes, S.J.K.; Yanhong, Z.

2004-01-01

Cathodoluminescence (CL) petrography provides a means of observing petrographic and compositional properties of geological samples not readily observable by other techniques. We report the low-magnification CL images of 60 sections of extraterrestrial materials. The images we report include ordinary chondrites (including type 3 ordinary chondrites and gas-rich regolith breccias), enstatite chondrites, CO chondrites and a CM chondrite, eucrites and a howardite, lunar highland regolith breccias, and lunar soils. The CL images show how primitive materials respond to parent body metamorphism, how the metamorphic history of EL chondrites differs from that of EH chondrites, how dark matrix and light clasts of regolith breccias relate to each other, how metamorphism affects eucrites, the texture of lunar regolith breccias and the distribution of crystallized lunar spherules ("lunar chondrules"), and how regolith working affects the mineral properties of lunar soils. More particularly, we argue that such images are a rich source of new information on the nature and history of these materials and that our efforts to date are a small fraction of what can be done. Copyright 2004 by the American Geophysical Union.

Shock State of Itokawa Regolith Grains

NASA Technical Reports Server (NTRS)

Zolensky, M.; Nishiizumi, K.; Mikouchi, T.; Chan, Q. H. S.; Martinez, J.; Caffee, M.

2014-01-01

One of the fundamental aspects of any astromaterial is its shock history, since this factor elucidates critical historical events, and also because shock metamorphism can alter primary mineralogical and petrographic features, and reset chronologies.

Memristive Properties of Thin Film Cuprous Oxide

DTIC Science & Technology

2011-03-01

Equation Chapter 1 Section 1 MEMRISTIVE PROPERTIES OF THIN FILM CUPROUS OXIDE THESIS Brett C...Force Base, Ohio APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED The views expressed in this thesis are those of the...MEMRISTIVE PROPERTIES OF THIN FILM CUPROUS OXIDE THESIS Presented to the Faculty Department of Engineering Physics Graduate School of

7 CFR 29.2438 - Thin Leaf (C Group).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 2 2013-01-01 2013-01-01 false Thin Leaf (C Group). 29.2438 Section 29.2438... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2438 Thin Leaf (C Group). This group consists of leaves usually grown at the center portion of the stalk. These leaves normally have a rounded tip, are thinner in...

7 CFR 29.2438 - Thin Leaf (C Group).

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 2 2014-01-01 2014-01-01 false Thin Leaf (C Group). 29.2438 Section 29.2438... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2438 Thin Leaf (C Group). This group consists of leaves usually grown at the center portion of the stalk. These leaves normally have a rounded tip, are thinner in...

7 CFR 29.2438 - Thin Leaf (C Group).

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 2 2011-01-01 2011-01-01 false Thin Leaf (C Group). 29.2438 Section 29.2438... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2438 Thin Leaf (C Group). This group consists of leaves usually grown at the center portion of the stalk. These leaves normally have a rounded tip, are thinner in...

7 CFR 29.2438 - Thin Leaf (C Group).

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Thin Leaf (C Group). 29.2438 Section 29.2438... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2438 Thin Leaf (C Group). This group consists of leaves usually grown at the center portion of the stalk. These leaves normally have a rounded tip, are thinner in...

7 CFR 29.2438 - Thin Leaf (C Group).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 2 2012-01-01 2012-01-01 false Thin Leaf (C Group). 29.2438 Section 29.2438... REGULATIONS TOBACCO INSPECTION Standards Grades § 29.2438 Thin Leaf (C Group). This group consists of leaves usually grown at the center portion of the stalk. These leaves normally have a rounded tip, are thinner in...

Lα and Mαβ X-ray production cross-sections of Bi by 6-30 keV electron impact

NASA Astrophysics Data System (ADS)

Liang, Y.; Xu, M. X.; Yuan, Y.; Wu, Y.; Qian, Z. C.; Chang, C. H.; Mei, C. S.; Zhu, J. J.; Moharram, K.

2017-12-01

In this paper, the Lα and Mαβ X-ray production cross-sections for Bi impacted by 6-30 keV electron have been measured. The experiments were performed at a Scanning Electron Microscope equipped with a silicon drift detector. The thin film with thick C substrate and the thin film deposited on self-supporting thin C film were both used as the targets to make a comparison. For the thick carbon substrate target, the Monte Carlo method has been used to eliminate the contribution of backscattering particles. The measured data are compared with the DWBA theoretical model and the experimental results in the literature. The experimental data for the thin film with thick C substrate target and the thin film deposited on self-supporting thin C film target are within reasonable gaps. The DWBA theoretical model gives good fit to the experimental data both for L- and M- shells. Besides, we also analyze the reasons why the discrepancies exist between our measurements and the experimental results in the literature.

Fieldpath Lunar Meteorite Graves Nunataks 06157, a Magnesian Piece of the Lunar Highlands Crust

NASA Technical Reports Server (NTRS)

Zeigler, Ryan A.; Korotev, R. L.; Korotev, R. L.

2012-01-01

To date, 49 feldspathic lunar meteorites (FLMs) have been recovered, likely representing a minimum of 35 different sample locations in the lunar highlands. The compositional variability among FLMs far exceeds the variability observed among highland samples in the Apollo and Luna sample suites. Here we will discuss in detail one of the compositional end members of the FLM suite, Graves Nunataks (GRA) 06157, which was collected by the 2006-2007 ANSMET field team. At 0.79 g, GRA 06157 is the smallest lunar meteorite so far recovered. Despite its small size, its highly feldspathic and highly magnesian composition are intriguing. Although preliminary bulk compositions have been reported, thus far no petrographic descriptions are in the literature. Here we expand upon the bulk compositional data, including major-element compositions, and provide a detailed petrographic description of GRA 06157.

Synfolding magnetization in the Jurassic Preuss Sandstone, Wyoming- Idaho-Utah thrust belt

USGS Publications Warehouse

Hudson, M.R.; Reynolds, R.L.; Fishman, N.S.

1989-01-01

The Jurassic Preuss Sandstone, exposed in five thrust plates of the Wyoming-Idaho-Utah thrust belt, carried directions of remanent magnetization that group most tightly after only partial unfolding. Field, petrographic, and rock magnetic evidence indicates that the carrier of this magnetization is detrital, low-Ti titanomagnetite. The detrital titanomagnetite was remagnetized at low temperatures (75??-150??C) probably completely during folding. Anisotropy of magnetic susceptibility and petrographic observations indicate that the detrital titanomagnetite has been affected by tectonic strain. The locus of acquisition of synfolding magnetization in the Preuss migrated in conjunction with deformation in the thrust belt. A model is presented in which synfolding magnetization was acquired during cooling and folding as strata moved up thrust ramps. A lack of reverse-polarity directions remains a puzzling feature of the remanence. -from Authors

Interaction of coeval felsic and mafic magmas from the Kanker granite, Pithora region, Bastar Craton, Central India

NASA Astrophysics Data System (ADS)

Elangovan, R.; Krishna, Kumar; Vishwakarma, Neeraj; Hari, K. R.; Ram Mohan, M.

2017-10-01

Field and petrographic studies are carried out to characterize the interactions of mafic and felsic magmas from Pithora region of the northeastern part of the Bastar Craton. The MMEs, syn-plutonic mafic dykes, cuspate contacts, magmatic flow textures, mingling and hybridization suggest the coeval emplacement of end member magmas. Petrographic evidences such as disequilibrium assemblages, resorption textures, quartz ocelli, rapakivi and poikilitic textures suggest magma mingling and mixing phenomena. Such features of mingling and mixing of the felsic and mafic magma manifest the magma chamber processes. Introduction of mafic magmas into the felsic magmas before initiation of crystallization of the latter, results in hybrid magmas under the influence of thermal and chemical exchange. The mechanical exchange occurs between the coexisting magmas due to viscosity contrast, if the mafic magma enters slightly later into the magma chamber, then the felsic magma starts to crystallize. Blobs of mafic magma form as MMEs in the felsic magma and they scatter throughout the pluton due to convection. At a later stage, if mafic magma enters the system after partial crystallization of felsic phase, mechanical interaction between the magmas leads to the formation of fragmented dyke or syn-plutonic mafic dyke. All these features are well-documented in the study area. Field and petrographic evidences suggest that the textural variations from Pithora region of Bastar Craton are the outcome of magma mingling, mixing and hybridization processes.

A nondestructive analytical method for stone meteorites and a controversial discrepancy

NASA Astrophysics Data System (ADS)

Fredriksson, K.; Brenner, P. R.; Fredriksson, B. J.; Olsen, E.

1997-01-01

A method is described for whole rock analyses of major elements in stone meteorites using the electron microprobe and requiring only powdering of the sample, most of which can be retrieved after analysis for additional analytical studies, such as INAA, RNAA and oxygen isotope analysis. Whole individual chondrules of _ 1 milligram can be analyzed. The method is especially attractive for meteorites in short supply, or of great rarity. A total of 398 meteorites were analyzed by this method. The results compare favorably with wet chemical analyses. A study was made of seventeen ordinary chondrites to compare their whole rock (metal free) compositions with the averaged compositions of eleven to thirty-eight of their respective individual chondrules (a total of 374 chondrules). The oxide ratio Al2O3/CaO is generally lower in chondrules than in their respective chondrites, the disparity being larger for petrographic grade 5 than for grade 3. Ordinary chondrites are not simply the sum of their respective chondrules. Furthermore, correlations between CaO, Al2O3 and TiO2 are strong for chondrules in unequilibrated chondrites and nonexistent in equilibrated chondrites. Also H, L and LL chondrite groups have similar bulk compositions within their respective groups, in spite of the different proportions of chondrules, kinds of chondrules, chondrule debris and matrix. All this brings into question the metamorphic classification in which high petrographic grades are the metamorphosed equivalents of low petrographic grades.

Seismic velocity deviation log: An effective method for evaluating spatial distribution of reservoir pore types

NASA Astrophysics Data System (ADS)

Shirmohamadi, Mohamad; Kadkhodaie, Ali; Rahimpour-Bonab, Hossain; Faraji, Mohammad Ali

2017-04-01

Velocity deviation log (VDL) is a synthetic log used to determine pore types in reservoir rocks based on a combination of the sonic log with neutron-density logs. The current study proposes a two step approach to create a map of porosity and pore types by integrating the results of petrographic studies, well logs and seismic data. In the first step, velocity deviation log was created from the combination of the sonic log with the neutron-density log. The results allowed identifying negative, zero and positive deviations based on the created synthetic velocity log. Negative velocity deviations (below - 500 m/s) indicate connected or interconnected pores and fractures, while positive deviations (above + 500 m/s) are related to isolated pores. Zero deviations in the range of [- 500 m/s, + 500 m/s] are in good agreement with intercrystalline and microporosities. The results of petrographic studies were used to validate the main pore type derived from velocity deviation log. In the next step, velocity deviation log was estimated from seismic data by using a probabilistic neural network model. For this purpose, the inverted acoustic impedance along with the amplitude based seismic attributes were formulated to VDL. The methodology is illustrated by performing a case study from the Hendijan oilfield, northwestern Persian Gulf. The results of this study show that integration of petrographic, well logs and seismic attributes is an instrumental way for understanding the spatial distribution of main reservoir pore types.

Quality and petrographic characteristics of Paleocene coals from the Hanna basin, Wyoming

USGS Publications Warehouse

Pierce, B.S.

1996-01-01

Coal beds from the Ferris and Hanna Formations, in the Hanna basin, south-central Wyoming, exhibit distinct differences in ash yield, sulfur content, and petrographic and palynologic constituents. These differences are interpreted to be controlled by tectonic changes of the Hanna basin and adjoining uplifts during evolutionary development, which, in turn, controlled mire chemistry and sedimentation. These conditions created two very different settings under which the peats developed during deposition of the Ferris and the Hanna Formations. In addition, there appears to be a geographic (latitudinal) and/or climatic control on the coal characteristics manifested by major differences of Paleocene coals in the Hanna basin compared to those in the Raton basin in Colorado and New Mexico and the Powder River basin in Wyoming.Coal beds from the Ferris and Hanna Formations, in the Hanna basin, south-central Wyoming, exhibit distinct differences in ash yield, sulfur content, and petrographic and palynologic constituents. These differences are interpreted to be controlled by tectonic changes of the Hanna basin and adjoining uplifts during evolutionary development, which, in turn, controlled mire chemistry and sedimentation. These conditions created two very different settings under which the peats developed during deposition of the Ferris and the Hanna Formations. In addition, there appears to be a geographic (latitudinal) and/or climatic control on the coal characteristics manifested by major differences of Paleocene coals in the Hanna basin compared to those in the Raton basin in Colorado and New Mexico and the Powder River basin in Wyoming.

Integrated geomechanical, petrographical and petrophysical study of the sandstones of the Wajid Group, SW Saudi Arabia

NASA Astrophysics Data System (ADS)

Benaafi, Mohammed; Hariri, Mustafa; Al-Shaibani, Abdulaziz; Abdullatif, Osman; Makkawi, Mohammed

2018-07-01

The Cambro-Permian siliciclastic succession in southwestern Saudi Arabia is represented by the Wajid Group, which consists mainly of fluvial, shallow marine, aeolian, and glacial sandstones. The Wajid Group comprises the Dibsiyah, Sanamah, Qalibah, Khusayyayn, and Juwayl Formations. It is exposed in the Wadi Al-Dawasir area and extends to Najran City. The sandstones of the Wajid Group serve as groundwater aquifers in the Wadi Al-Dawasir and Najran areas and host hydrocarbon (mainly gas) reservoirs in the Rub' Al-Khali Basin. This study aims to characterize the geomechanical properties (rock strength and Young's modulus) of the sandstones of the Wajid Group using field and experimental techniques. A further objective is to investigate the relationships between the geomechanical properties and the petrographical and petrophysical properties of the studied sandstones. The geomechanical properties of the studied sandstones vary from glacial to non-glacial sandstones, as the glacial sandstones display high values of the geomechanical properties with high variability indices. Four geological factors including grain size, cement content, porosity and permeability were observed as the main controls on the geomechanical behaviour of the studied sandstones except for the Khusayyayn sandstone, where the mineral composition was also important. Significant correlations were observed between the petrographical and petrophysical properties and the geomechanical properties of the glacial sandstones. Predictive models of the geomechanical properties (RN, UCS, and E) were generated using regression analysis to account for the glacial sandstones.

Evaluating the Relationships Between NTNU/SINTEF Drillability Indices with Index Properties and Petrographic Data of Hard Igneous Rocks

NASA Astrophysics Data System (ADS)

Aligholi, Saeed; Lashkaripour, Gholam Reza; Ghafoori, Mohammad; Azali, Sadegh Tarigh

2017-11-01

Thorough and realistic performance predictions are among the main requisites for estimating excavation costs and time of the tunneling projects. Also, NTNU/SINTEF rock drillability indices, including the Drilling Rate Index™ (DRI), Bit Wear Index™ (BWI), and Cutter Life Index™ (CLI), are among the most effective indices for determining rock drillability. In this study, brittleness value (S20), Sievers' J-Value (SJ), abrasion value (AV), and Abrasion Value Cutter Steel (AVS) tests are conducted to determine these indices for a wide range of Iranian hard igneous rocks. In addition, relationships between such drillability parameters with petrographic features and index properties of the tested rocks are investigated. The results from multiple regression analysis revealed that the multiple regression models prepared using petrographic features provide a better estimation of drillability compared to those prepared using index properties. Also, it was found that the semiautomatic petrography and multiple regression analyses provide a suitable complement to determine drillability properties of igneous rocks. Based on the results of this study, AV has higher correlations with studied mineralogical indices than AVS. The results imply that, in general, rock surface hardness of hard igneous rocks is very high, and the acidic igneous rocks have a lower strength and density and higher S20 than those of basic rocks. Moreover, DRI is higher, while BWI is lower in acidic igneous rocks, suggesting that drill and blast tunneling is more convenient in these rocks than basic rocks.

Petrographic and anatomical characteristics of plant material from two peat deposits of Holocene and Miocene age, Kalimantan, Indonesia

USGS Publications Warehouse

Moore, T.A.; Hilbert, R.E.

1992-01-01

Samples from two peat-forming environments of Holocene and Miocene age in Kalimantan (Borneo), Indonesia, were studied petrographically using nearly identical sample preparation and microscopic methodologies. Both deposits consist of two basic types of organic material: plant organs/tissues and fine-grained matrix. There are seven predominant types of plant organs and tissues: roots possessing only primary growth, stems possessing only primary growth, leaves, stems/roots with secondary growth, secondary xylem fragments, fragments of cork cells, and macerated tissue of undetermined origin. The fine-grained matrix consists of fragments of cell walls and cell fillings, fungal remains, spores and pollen grains, and resin. Some of the matrix material does not have distinct grain boundaries (at ??500) and this material is designated amorphous matrix. The major difference between the Holocene peat and Miocene lignite in reflected light, oil immersion is a loss of red coloration in the cell walls of tissue in the lignite, presumably due to loss of cellulosic compounds. In addition, cortex and phloem tissue (hence primary roots and stems) are difficult to recognize in the lignite, probably because these large, thin-walled tissues are more susceptible to microbial degradation and compaction. Particle size in both peat and lignite samples display a bimodal distribution when measurements are transformed to a - log2 or phi (??), scale. Most plant parts have modes of 2-3?? (0.25 - 0.125 mm), whereas the finer-grained particulate matrix has modes of 7-9?? (0.008-0.002 mm). This similarity suggest certain degradative processes. The 2-3?? range may be a "stable" size for plant parts (regardless of origin) because this is a characteristics of a substrate which is most suitable for plant growth in peat. The finer-grained matrix material (7-9??) probably results from fungal decay which causes plant material to weaken and with slight physical pressure to shatter into its component parts, i.e. fragments of cell walls and fillings. The absence of differences in particle size between the peat and lignite also indicate little compaction of organic components; rather an extreme loss in water content and pore space has occurred from between the particles of organic material. ?? 1992.

Brown coal maceral distributions in a modern domed tropical Indonesian peat and a comparison with maceral distributions in Middle Pennsylvanian–age Appalachian bituminous coal beds

USGS Publications Warehouse

Grady, William C.; Eble, Cortland F.; Neuzil, Sandra G.

1993-01-01

Analyses of modern Indonesian peat samples reveal that the optical characteristics of peat constituents are consistent with the characteristics of macerals observed in brown coal and, as found by previous workers, brown-coal maceral terminology can be used in the analysis of modern peat. A core from the margin and one from near the center of a domed peat deposit in Riau Province, Sumatra, reveal that the volume of huminite macerals representing well-preserved cell structures (red, red-gray, and gray textinite; ulminite; and corpo/textinite) decreases upward. Huminite macerals representing severely degraded (<20 microns) cellular debris (degraded textinite, attrinite, and densinite) increase uniformly from the base to the surface. Greater degradation of the huminite macerals in the upper peat layers in the interior of the deposit is interpreted to be the result of fungal activity that increased in response to increasingly aerobic conditions associated with the doming of the peat deposit. Aerobic conditions concurrent with the activities of fungi may result in incipient oxidation of the severely degraded huminite macerals. This oxidation could lead to the formation of degradosemifusinite, micrinite, and macrinite maceral precursors in the peat, which may become evident only upon coalification. The core at the margin was petrographically more homogeneous than the core from the center and was dominated by well-preserved huminite macerals except in the upper 1 m, which showed signs of aerobic degradation and was similar to the upper 1 m of the peat in the interior of the deposit.The Stockton and other Middle Pennsylvanian Appalachian coal beds show analogous vertical trends in vitrinite maceral composition. The succession from telocollinite-rich, bright coal lithotypes in the lower benches upward to thin-banded/matrix collinite and desmocollinite in higher splint coal benches is believed to reflect a progression similar to that from the well-preserved textinite macerals in the lower portions of the peat cores to severely fragmented and degraded cellular materials (degraded textinite, attrinite, and densinite) in the upper portions of the cores. This petrographic sequence from bright to splint coal in the Stockton and other Middle Pennsylvanian coal beds supports previous interpretations of an upward transition from planar to domed swamp accumulations.

Petrography and geochemistry of the San Miguel lignite, Jackson Group (Eocene), south Texas

USGS Publications Warehouse

Warwick, Peter D.; Crowley, Sharon S.; Ruppert, Leslie F.; Pontolillo, James

1996-01-01

The San Miguel lignite deposit (late Eocene, lower Jackson Group) of south Texas consists of four or more thin (generally < 1 m thick) lignite benches that are separated by claystone and mudstone partings. The partings are composed of altered volcanic air-fall ash that has been reworked by tidal or channel processes associated with a back-barrier depositional environment. The purpose of this study is to examine the relationship between the ash yield and the petrographic and geochemical characteristics of the San Miguel lignite as mined. Particular attention is given to 12 of the environmentally sensitive trace elements (As, Be, Cd, Cr, Co, Hg, Mn, Ni, Pb, Sb, Se, and U) that have been identified as possible hazardous air pollutants (HAPs) by the United States Clean Air Act Amendments of 1990. A total of 29 rock and lignite samples were collected and characterized by geochemical and petrographic methods. The major conclusions of the study are as follows: (1) The distribution of Mn is inversely related to the ash yield of the lignite samples. This indicates an organic affinity, or an association with finely disseminated minerals in the lignite that contain this element. (2) On a whole-coal basis, the concentration of the HAPs' element Pb is positively related to ash yield in lignite samples. This indicates an inorganic affinity for Pb. (3) Average whole-coal concentrations of As, Be, Sb, and U in the San Miguel samples are greater than published averages for these elements in other U.S. lignites. (4) The upper and lower lignite benches of the San Miguel deposit are both ash- and algal-rich, indicating that these intervals were probably deposited in wetter conditions than those in which the middle intervals formed. (5) The dominance of the eugelinite maceral subgroup over the huminite subgroup indicates that the San Miguel lignites were subjected to peat-forming conditions (either biogenic or chemical) that enabled degradation of wood cellular material into matrix gels, or that the plants that formed these lignite benches were less woody and more prone to formation of matrix gels. (6) An inertinite-rich layer (top of the B bed) might have formed from widespread oxidation of the San Miguel peat as a result of a volcanic ash fall which was subsequently reworked.

A simple method for maintaining relative positions of separate tissue elements during processing for electron microscopy.

PubMed

Stirling, C A

1978-09-01

Molten (328 K) 20% gelatin is used as a 'glue' to hold together separate tissue elements or tissue elements that may be separated when cutting small blocks of tissue for plastic embedding. Standard aldehyde and osmium fixation, dehydration and epoxy embedding are compatible with this as is semi-thin sectioning for light microscopy or thin sectioning for electron microscopy.

Maceral and palynomorph facies from two tertiary peat-forming environments in the Powder River Basin, U.S.A.

USGS Publications Warehouse

Moore, T.A.; Stanton, R.W.; Pocknall, D.T.; Glores, R.M.

1990-01-01

The differences between the depositional settings of the Smith and Anderson subbituminous coal beds (Paleocene, central Powder River Basin, U.S.A.) are interpreted on the basis of their petrographic composition and palynologic assemblages. The Smith coal bed is relatively thin ( 50 m) sandstone bodies of an abandoned meander-belt complex, the coal bed is generally thicker (> 7 m) and more widespread (> 15 km) in extent than the Smith coal bed. The sands provided a relatively stable, poorly compactable platform that was favorable to the growth of large, arborescent vegetation, such as the dominant ancestral Glyptostrobus, as well as ancestral Nyssa, Carya, and Betulaceae in a well-drained but moist swamp environment. The stability of the peat-forming environment resulted in a raised peat deposit of relatively uniform paleoflora and peat composition. In the thicker areas of the Anderson coal bed, the upward increase in carbonized plant components indicates a progressively drier or better-drained swamp environment. Intervals within the coal bed that overlie or are lateral to crevasse-splay deposits contain a high concentration of pollen attributable to Pterocarya and an absence of carbonized plant remains, an indication that ancestral Pterocarya preferred a water-saturated environment close to the edge of the swamp where detrial influx occurred. ?? 1990.

Probable calcified metaphytes in the latest Proterozoic Nama Group, Namibia: origin, diagenesis, and implications

NASA Technical Reports Server (NTRS)

Grant, S. W.; Knoll, A. H.; Germs, G. J.

1991-01-01

Samples from the Huns Limestone Member, Urusis Formation, Nama Group, at two adjacent localities in southern Namibia contain thin foliose to arched, sheet-like carbonate crusts that are 100-500 micrometers thick and up to 5 cm in lateral dimension. Morphologic, petrographic, and geochemical evidence supports the interpretation of these delicate crusts as biogenic, most likely the remains of calcified encrusting metaphytes. The original sediments of the fossiliferous samples contained aragonitic encrusting algae, botryoidal aragonite cements, and an aragonite mud groundmass. Spherulites within the precursor mud could represent bacterially induced mineral growths or the concretions of marine rivularian cyanobacteria. Original textures were severely disrupted during the diagenetic transition of aragonite to low-magnesian calcite, but some primary structures remain discernible as ghosts in the neomorphic mosaic. Gross morphology, original aragonite mineralogy, and hypobasal calcification indicate that the crusts are similar to late Paleozoic phylloid algae and extant peyssonnelid red algae. Structures interpreted as possible conceptacles also suggest possible affinities with the Corallinaceae. Two species of Cloudina, interpreted as the remains of a shelly metazoan, are also known from limestones in the Nama Group. It is possible, therefore, that skeletalization in metaphytes and animals arose nearly simultaneously near the end of the Proterozoic Eon.

Ultrasonic Nondestructive Evaluation Techniques Applied to the Quantitative Characterization of Textile Composite Materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1997-01-01

In this Progress Report, we describe our further development of advanced ultrasonic nondestructive evaluation methods applied to the characterization of anisotropic materials. We present images obtained from experimental measurements of ultrasonic diffraction patterns transmitted through water only and transmitted through water and a thin woven composite. All images of diffraction patterns have been included on the accompanying CD-ROM in the JPEG format and Adobe TM Portable Document Format (PDF), in addition to the inclusion of hardcopies of the images contained in this report. In our previous semi-annual Progress Report (NAG 1-1848, December, 1996), we proposed a simple model to simulate the effect of a thin woven composite on an insonifying ultrasonic pressure field. This initial approach provided an avenue to begin development of a robust measurement method for nondestructive evaluation of anisotropic materials. In this Progress Report, we extend that work by performing experimental measurements on a single layer of a five-harness biaxial woven composite to investigate how a thin, yet architecturally complex, material interacts with the insonifying ultrasonic field. In Section 2 of this Progress Report we describe the experimental arrangement and methods for data acquisition of the ultrasonic diffraction patterns upon transmission through a thin woven composite. We also briefly describe the thin composite specimen investigated. Section 3 details the analysis of the experimental data followed by the experimental results in Section 4. Finally, a discussion of the observations and conclusions is found in Section 5.

QEMSCAN+LA-ICP-MS: a 'big data' generator for sedimentary provenance analysis

NASA Astrophysics Data System (ADS)

Vermeesch, Pieter; Rittner, Martin; Garzanti, Eduardo

2017-04-01

Sedimentary provenance may be traced by 'fingerprinting' sediments with chemical, mineralogical or isotopic means. Normally, each of these provenance proxies is characterised on a separate aliquot of the same sample. For example, the chemical composition of the bulk sample may be analysed by X-ray fluorescence (XRF) on one aliquot, framework petrography on another, heavy mineral analysis on a density separate of a third split, and zircon U-Pb dating on a further density separate of the heavy mineral fraction. The labour intensity of this procedure holds back the widespread application of multi-method provenance studies. We here present a new method to solve this problem and avoid mineral separation by coupling a QEMSCAN electron microscope to an LA-ICP-MS instrument and thereby generate all four aforementioned provenance datasets as part of the same workflow. Given a polished hand specimen, a petrographic thin section, or a grain mount, the QEMSCAN+LA-ICP-MS method produces chemical and mineralogical maps from which the X-Y coordinates of the datable mineral are extracted. These coordinates are subsequently passed on to the laser ablation system for isotopic and, hence, geochronological analysis. In the process of finding all the zircons in a sediment grain mount, the QEMSCAN yields the compositional and mineralogical compositions as byproducts. We have applied the new QEMSCAN+LA-ICP-MS instrument suite to over 100 samples from three large sediment routing systems: (1) the Tigris-Euphrates river catchments and Rub' Al Khali desert in Arabia; (2) the Nile catchment in northeast Africa and (3) desert and beach sands between the Orange and Congo rivers in southwest Africa. These studies reveal (1) that Rub' Al Khali sand is predominantly derived from the Arabian Shield and not from Mesopotamia; (2) that the Blue Nile is the principal source of Nile sand; and (3) that Orange River sand is carried northward by longshore drift nearly 1,800km from South Africa to southern Angola. In addition to these geological findings, the first applications of QEMSCAN+LA-ICP-MS highlight some key advantages of the new workflow over traditional provenance analysis: (a) the new method not only increases sample throughput but also improves data quality by reducing significant biases associated with mineral separation and grain selection; (b) the three case studies highlight the importance of zircon 'fertility' for interpreting detrital zircon U-Pb datasets, and the ability of QEMSCAN to quantify this crucial parameter semi-automatically; (c) QEMSCAN+LA-ICP-MS provides an opportunity to add textural information to detrital geochronology and, for example, quantify possible grain-size dependence of U-Pb age distributions. But besides these advantages, the three case studies also reveal a number of limitations: (a) mineral identification by QEMSCAN is not as reliable as commonly achieved by human observers; (b) heavy mineral compositions obtained by QEMSCAN cannot easily be compared with conventional point counting data; and (c) apparent grain sizes can be greatly affected by polishing artefacts. In conclusion, QEMSCAN+LA-ICP-MS is a transformational new technique for provenance analysis but should be used with caution, in combination with conventional petrographic and heavy mineral techniques.

A new methodology for the diagnostics of architectural elements in historical buildings

NASA Astrophysics Data System (ADS)

Casula, Giuseppe; Fais, Silvana; Cuccuru, Francesco; Ligas, Paola; Giovanna Bianchi, Maria

2016-04-01

A new methodology is presented consisting of a multi-step procedure based on the integrated application of different diagnostic techniques aimed at recognizing altered and unaltered parts of architectural elements of ancient buildings and at identifying zones where structural damage has occurred on their surface. The methodology was tested on a historical building of the monumental compound in Piazza Palazzo in the historical center of the town of Cagliari (Italy). Three types of carbonate building materials have been used historically to construct ancient monuments in the historical center of Cagliari, which in order of increasing hardness are: Pietra Cantone, Tramezzario and Pietra Forte. Our methodology begins with an accurate microscopic examination of petrographic thin sections and scanning electron microscope (SEM) analysis of the above carbonate materials in order to identify their textural characteristics and especially the nature and distribution of their porosity. Other rock properties such as wet and dry bulk density were calculated from saturated and dry mass and volume respectively. In a second step we used a Leica HDS-6200 terrestrial laser scanner (TLS) to 3D model some building of the studied monumental compound (Piazza Palazzo). Surface geometrical anomalies have been modeled for the most interesting architectural elements, such as a Pietra Cantone portal in Late Gothic style inside the Antico Palazzo di Città, a historical building that hosts the civic museum bearing the same name. Since TLS technology is characterized by high productivity but is unable to investigate the inner parts of the studied materials, a third step of our procedure was complemented by several ultrasonic in situ and laboratory tests in the 54kHz - 82kHz range. The ultrasonic parameters, especially longitudinal and transversal velocities, can be measured very accurately and correlated with various material properties with reasonable confidence. This task has two objectives: one is to compare the petrographical and petrophysical rock properties with the elastic-dynamic ones, while the other is to compare TLS geometrical anomalies with the anomalies of the velocity field detected with ultrasonic methodology, which is very effective in detecting altered and/or damaged zones both on the surface and inside the building materials of architectural elements. Analogies between TLS surface geometrical anomalies and the ultrasonic velocity field are evident at the surface and in shallow parts of the investigated architectural elements, as in the mentioned Pietra Cantone ancient portal. This study illustrates how the integrated application of TLS technology and the ultrasonic method contributes in overcoming ambiguities in the interpretation of the individual dataset. Therefore the methodology proposed in this study has proved to be effective in giving useful indications aimed at formulating a recovery and preservation plan for a monumental structure and to monitor its conservation status in time. Acknowledgements: We thank the Cagliari Town Hall and the management of the Civic Museum Antico Palazzo di Città for their kind permission to work on the Museum. This work was supported by Regione Autonoma della Sardegna (Sardinian Autonomous Region), Regional Law 7th August 2007, no. 7, Promotion of scientific research and technological innovation in Sardinia.

Histological evidence for muscle insertion in extant amniote femora: implications for muscle reconstruction in fossils.

PubMed

Petermann, Holger; Sander, Martin

2013-04-01

Since the 19th century, identification of muscle attachment sites on bones has been important for muscle reconstructions, especially in fossil tetrapods, and therefore has been the subject of numerous biological and paleontological studies. At the microscopic level, in histological thin sections, the only features that can be used reliably for identifying tendon-bone or muscle-tendon-bone interactions are Sharpey's fibers. Muscles, however, do not only attach to the bone indirectly with tendons, but also directly. Previous studies failed to provide new indicators for muscle attachment, or to address the question of whether muscles with direct attachment can be identified histologically. However, histological identification of direct muscle attachments is important because these attachments do not leave visible marks (e.g. scars and rugosities) on the bone surface. We dissected the right hind limb and mapped the muscle attachment sites on the femur of one rabbit (Oryctolagus cuniculus), one Alligator mississippiensis, and one turkey (Meleagris cuniculus). We then extracted the femur and prepared four histological thin sections for the rabbit and the turkey and five histological thin sections for the alligator. Sharpey's fibers, vascular canal orientation, and a frayed periosteal margin can be indicators for indirect but also direct muscle attachment. Sharpey's fibers can be oriented to the cutting plane of the thin section at high angles, and two Sharpey's fibers orientations can occur in one area, possibly indicating a secondary force axis. However, only about 60% of mapped muscle attachment sites could be detected in thin sections, and frequently histological features suggestive of muscle attachment occurred outside mapped sites. While these insights should improve our ability to successfully identify and reconstruct muscles in extinct species, they also show the limitations of this approach. © 2013 The Authors Journal of Anatomy © 2013 Anatomical Society.

Histological evidence for muscle insertion in extant amniote femora: implications for muscle reconstruction in fossils

PubMed Central

Petermann, Holger; Sander, Martin

2013-01-01

Since the 19th century, identification of muscle attachment sites on bones has been important for muscle reconstructions, especially in fossil tetrapods, and therefore has been the subject of numerous biological and paleontological studies. At the microscopic level, in histological thin sections, the only features that can be used reliably for identifying tendon–bone or muscle–tendon-bone interactions are Sharpey's fibers. Muscles, however, do not only attach to the bone indirectly with tendons, but also directly. Previous studies failed to provide new indicators for muscle attachment, or to address the question of whether muscles with direct attachment can be identified histologically. However, histological identification of direct muscle attachments is important because these attachments do not leave visible marks (e.g. scars and rugosities) on the bone surface. We dissected the right hind limb and mapped the muscle attachment sites on the femur of one rabbit (Oryctolagus cuniculus), one Alligator mississippiensis, and one turkey (Meleagris cuniculus). We then extracted the femur and prepared four histological thin sections for the rabbit and the turkey and five histological thin sections for the alligator. Sharpey's fibers, vascular canal orientation, and a frayed periosteal margin can be indicators for indirect but also direct muscle attachment. Sharpey's fibers can be oriented to the cutting plane of the thin section at high angles, and two Sharpey's fibers orientations can occur in one area, possibly indicating a secondary force axis. However, only about 60% of mapped muscle attachment sites could be detected in thin sections, and frequently histological features suggestive of muscle attachment occurred outside mapped sites. While these insights should improve our ability to successfully identify and reconstruct muscles in extinct species, they also show the limitations of this approach. PMID:23439026

Evaporation thermal anslysis of Swallow-tailed Axial-grooved Heat Pipe

NASA Astrophysics Data System (ADS)

Zhang, Renping

2018-03-01

A detailed mathematical model that describes evaporating characteristics through thin liquid film at the evaporator section of swallow-tailed axial-grooved heat pipe was developed. The numerical simulation results about thin film profile, liquid-vapour interface temperature, evaporating rate and heat flux at the evaporating thin film region were given by the current investigation and the effect of superheat on the liquid-vapour interface temperature, evaporating mass rate and heat flux was discussed. Meanwhile, thermal model of the meniscus region at the evaporating section was developed to calculate the rate of heat transfer. The ratio of the heat conduction in the evaporating thin liquid film region and total heat rate were also discussed. It is indicated that the thickness of thin liquid film rises in a nearly linear fashion. The disjoining pressure can be neglected with increasing the liquid film thickness, tends to be negligibly small. The heat transfer rate at the intrinsic meniscus cannot be compared with that of the evaporating liquid film region.

Concrete barrier distress in La Grande, Oregon.

DOT National Transportation Integrated Search

2008-04-01

Several precast concrete barriers in eastern Oregon were noted to be deteriorating at an advanced rate. The ODOT : Research Unit took several core samples from the barriers and conducted analyses. Petrographic evaluations determined : that the strong...

Axial Crushing of Thin-Walled Columns with Octagonal Section: Modeling and Design

NASA Astrophysics Data System (ADS)

Liu, Yucheng; Day, Michael L.

This chapter focus on numerical crashworthiness analysis of straight thinwalled columns with octagonal cross sections. Two important issues in this analysis are demonstrated here: computer modeling and crashworthiness design. In the first part, this chapter introduces a method of developing simplified finite element (FE) models for the straight thin-walled octagonal columns, which can be used for the numerical crashworthiness analysis. Next, this chapter performs a crashworthiness design for such thin-walled columns in order to maximize their energy absorption capability. Specific energy absorption (SEA) is set as the design objective, side length of the octagonal cross section and wall thickness are selected as design variables, and maximum crushing force (Pm) occurs during crashes is set as design constraint. Response surface method (RSM) is employed to formulate functions for both SEA and Pm.

Grazing Incidence Cross-Sectioning of Thin-Film Solar Cells via Cryogenic Focused Ion Beam: A Case Study on CIGSe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sardashti, Kasra; Haight, Richard; Anderson, Ryan

2016-06-22

Cryogenic focused ion beam (Cryo-FIB) milling at near-grazing angles is employed to fabricate cross-sections on thin Cu(In,Ga)Se2 with >8x expansion in thickness. Kelvin probe force microscopy (KPFM) on sloped cross sections showed reduction in grain boundaries potential deeper into the film. Cryo Fib-KPFM enabled the first determination of the electronic structure of the Mo/CIGSe back contact, where a sub 100 nm thick MoSey assists hole extraction due to 45 meV higher work function. This demonstrates that CryoFIB-KPFM combination can reveal new targets of opportunity for improvement in thin-films photovoltaics such as high-work-function contacts to facilitate hole extraction through the backmore » interface of CIGS.« less

Influence of gating design on microstructure and fluidity of thin sections AA320.0 cast hypo-eutectic Al-Si alloy

NASA Astrophysics Data System (ADS)

Ramadan, Mohamed

2018-05-01

Influence of gating design especially number of ingrates on microstructure and fluidity of thin sections of 2, 4, 6 mm AA320.0 cast hypo-eutectic Al-Si alloy was evaluated for sand casting molding technique. Increasing the number of ingates improves the microstructe to be fine and more globular. About 87 μm of α-Al grain size, 0.6 α-Al grain sphericity and 37 μm dendrite arm spacing DAS are achieved by using 4 ingates in gating system. Increasing the number of ingates up to 3 increases hardness, filling area and related fluditiy of all cast samples. The minimum thickness of 2.5 mm for each ingate should be considered in order to successfully production of high quality light weight thin sections castings in sand mold.

In situ hybridization at the electron microscope level: localization of transcripts on ultrathin sections of Lowicryl K4M-embedded tissue using biotinylated probes and protein A-gold complexes

PubMed Central

1986-01-01

A technique has been developed for localizing hybrids formed in situ on semi-thin and ultrathin sections of Lowicryl K4M-embedded tissue. Biotinylated dUTP (Bio-11-dUTP and/or Bio-16-dUTP) was incorporated into mitochondrial rDNA and small nuclear U1 probes by nick- translation. The probes were hybridized to sections of Drosophila ovaries and subsequently detected with an anti-biotin antibody and protein A-gold complex. On semi-thin sections, probe detection was achieved by amplification steps with anti-protein A antibody and protein A-gold with subsequent silver enhancement. At the electron microscope level, specific labeling was obtained over structures known to be the site of expression of the appropriate genes (i.e., either over mitochondria or over nuclei). The labeling pattern at the light microscope level (semi-thin sections) was consistent with that obtained at the electron microscope level. The described nonradioactive procedures for hybrid detection on Lowicryl K4M-embedded tissue sections offer several advantages: rapid signal detection: superior morphological preservation and spatial resolution; and signal-to-noise ratios equivalent to radiolabeling. PMID:3084498

Magnetic, in situ, mineral characterization of Chelyabinsk meteorite thin section

NASA Astrophysics Data System (ADS)

Nabelek, Ladislav; Mazanec, Martin; Kdyr, Simon; Kletetschka, Gunther

2015-06-01

Magnetic images of Chelyabinsk meteorite's (fragment F1 removed from Chebarkul lake) thin section have been unraveled by a magnetic scanning system from Youngwood Science and Engineering (YSE) capable of resolving magnetic anomalies down to 10-3 mT range from about 0.3 mm distance between the probe and meteorite surface (resolution about 0.15 mm). Anomalies were produced repeatedly, each time after application of magnetic field pulse of varying amplitude and constant, normal or reversed, direction. This process resulted in both magnetizing and demagnetizing of the meteorite thin section, while keeping the magnetization vector in the plane of the thin section. Analysis of the magnetic data allows determination of coercivity of remanence (Bcr) for the magnetic sources in situ. Value of Bcr is critical for calculating magnetic forces applicable during missions to asteroids where gravity is compromised. Bcr was estimated by two methods. First method measured varying dipole magnetic field strength produced by each anomaly in the direction of magnetic pulses. Second method measured deflections of the dipole direction from the direction of magnetic pulses. Bcr of magnetic sources in Chelyabinsk meteorite ranges between 4 and 7 mT. These magnetic sources enter their saturation states when applying 40 mT external magnetic field pulse.

Effect of dropped plies on the strength of graphite-epoxy laminates

NASA Technical Reports Server (NTRS)

Curry, James M.; Johnson, Eric R.; Starnes, James H., Jr.

1987-01-01

The reduction in the compressive and tensile strengths of graphite-epoxy laminates with thickness discontinuities due to dropped plies was studied by experiment and analysis. The specimens were fabricated with all the dropped plies lumped together in the center of a sixteen-ply quasi-isotropic layup, such that one surface was flat and the slope of the opposite surface changed abruptly at the dropped ply location to accommodate the thickness change. Even though the thick and thin sections are symmetrically laminated, there exists bending-extension coupling due to the geometric eccentricity of the middle planes of the thick and thin sections. Experiments were conducted on fifty-four specimens that differed in the configuration of the dropped plies only. The strength of a laminate with dropped plies is less than the strength of its thin section, and the compressive strength of a laminate with dropped plies is less than its tensile strength. The reduction in strength is directly related to the axial stiffness change between the thick and thin sections. To examine the mechanism of failure, the three-dimensional state of stress in the dropped ply region was evaluated by the finite element method. A tensile interlaminar criterion predicted the correct location of failure, but underestimated the failure load.

The New Lunar Meteorite DEW 12007

NASA Astrophysics Data System (ADS)

Collareta, A.; D'Orazio, M.; Gemelli, M.; Pack, A.; Folco, L.

2014-09-01

The new lunar meteorite DEW 12007 was found in Antarctica in January 2013 by PNRA. DEW 12007 has been classified as a regolithic breccia of mingled composition. In our abstract we present its first-order geochemical and petrographic features.

Impact of petrographic properties on the burning behavior of pulverized coal using a drop tube furnace

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. Biswas; N. Choudhury; S. Ghosal

The combustion behavior of three Indian coals of different rank with wide variation in ash content and maceral compositions were studied using a drop tube furnace (DTF). Each coal was pulverized into a specific size (80% below 200 mesh) and fed into the DTF separately. The DTF runs were carried out under identical conditions for all of the coals. The carbon burnout was found out from the chemical analyses of the feed coals and the char samples collected from different ports of the DTF. Char morphology analyses was carried on the burnout residues of the top port. The top portmore » results show better burnout of the lower rank coals which however was not observed in the last port. An attempt has been made to account for this variation in terms of rank and petrographic parameters of the respective coals. 20 refs., 1 fig., 6 tabs.« less

Prediction of coal grindability from exploration data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gomez, M.; Hazen, K.

1970-08-01

A general prediction model for the Hardgrove grindability index was constructed from 735 coal samples using the proximate analysis, heating value, and sulfur content. The coals used to develop the general model ranged in volatile matter from 12.8 to 49.2 percent, dry basis, and had grindability indexes ranging from 35 to 121. A restricted model applicable to bituminous coals having grindabilities in the 40 to 110 range was developed from the proximate analysis and the petrographic composition of the coal. The prediction of coal grindability within a single seam was also investigated. The results reported support the belief that mechanicalmore » properties of the coal are related to both chemical and petrographic factors of the coal. The mechanical properties coal may be forecast in advance of mining, because the variables used as input to the prediction models can be measured from drill core samples collected during exploration.« less

Petrographic and major elements results as indicator of the geothermal potential in Java

NASA Astrophysics Data System (ADS)

Indarto, S.; Setiawan, I.; Kausar, A.; Permana, dan H.

2018-02-01

Geothermal manifestations existed in West Java (Cilayu, Papandayan Mountain, Telagabodas, Karaha, Tampomas Mountain), Central Java (Slamet Mountain, Dieng) and East Java (Argopuro Mountain) show a difference in their mineral and geochemical compositions. The petrographic analysis of volcanic rocks from Garut (West Java) are basalt, andesite basaltic and andesite. However, based on SiO2 vs K2O value, those volcanic rocks have wide ranges of fractionated magma resulting basalt - basaltic andesite to dacitic in composition rather than those of Slamet Mountain, Dieng, and Argopuro Mountain areas which have a narrower range of fractionation magma resulting andesite basaltic and andesite in compositions. The volcanic rocks from Garut show tholeiitic affinity and calc-alkaline affinity. The geothermal potential of Java is assumed to be related to the magma fractionation level. Geothermal potential of West Java (Garut) is higher than that of Central Java (Slamet Mountain, Dieng) and East Java (Argopuro Mountain).

Evolution of tholeiitic diabase sheet systems in the eastern United States: examples from the Culpeper Basin, Virginia-Maryland, and the Gettysburg Basin, Pennsylvania

USGS Publications Warehouse

Woodruff, L.G.; Froelich, A.J.; Belkin, H.E.; Gottfried, D.

1995-01-01

High-TiO2, quartz-normative (HTQ) tholeiite sheets of Early Jurassic age have intruded mainly Late Triassic sedimentary rocks in several early Mesozoic basins in the eastern US. Field observations, petrographic study, geochemical analyses and stable isotope data from three HTQ sheet systems were used to develop a general model of magmatic differentiation and magmatic-hydrothermal interaction for HTQ sheets. The three sheet systems have remarkably similar major-oxide and trace-element compositions. Cumulus and evolved diabase in comagmatic sheets separated by tens of kilometers are related by igneous differentiation. Differentiated diabase in all three sheets have petrographic and geochemical signatures and fluid inclusions indicating hydrothermal alteration beginning near magmatic temperatures and continuing to relatively low temperatures. Sulfur and oxygen isotope data are consistent with a magmatic origin for the hydrothermal fluid. -from Authors

SWI or T2*: which MRI sequence to use in the detection of cerebral microbleeds? The Karolinska Imaging Dementia Study.

PubMed

Shams, S; Martola, J; Cavallin, L; Granberg, T; Shams, M; Aspelin, P; Wahlund, L O; Kristoffersen-Wiberg, M

2015-06-01

Cerebral microbleeds are thought to have potentially important clinical implications in dementia and stroke. However, the use of both T2* and SWI MR imaging sequences for microbleed detection has complicated the cross-comparison of study results. We aimed to determine the impact of microbleed sequences on microbleed detection and associated clinical parameters. Patients from our memory clinic (n = 246; 53% female; mean age, 62) prospectively underwent 3T MR imaging, with conventional thick-section T2*, thick-section SWI, and conventional thin-section SWI. Microbleeds were assessed separately on thick-section SWI, thin-section SWI, and T2* by 3 raters, with varying neuroradiologic experience. Clinical and radiologic parameters from the dementia investigation were analyzed in association with the number of microbleeds in negative binomial regression analyses. Prevalence and number of microbleeds were higher on thick-/thin-section SWI (20/21%) compared with T2*(17%). There was no difference in microbleed prevalence/number between thick- and thin-section SWI. Interrater agreement was excellent for all raters and sequences. Univariate comparisons of clinical parameters between patients with and without microbleeds yielded no difference across sequences. In the regression analysis, only minor differences in clinical associations with the number of microbleeds were noted across sequences. Due to the increased detection of microbleeds, we recommend SWI as the sequence of choice in microbleed detection. Microbleeds and their association with clinical parameters are robust to the effects of varying MR imaging sequences, suggesting that comparison of results across studies is possible, despite differing microbleed sequences. © 2015 by American Journal of Neuroradiology.

Electrical contacts to thin layers of Bi2Sr2CaCu2O8+δ

NASA Astrophysics Data System (ADS)

Suzuki, Shota; Taniguchi, Hiroki; Kawakami, Tsukasa; Cosset-Cheneau, Maxen; Arakawa, Tomonori; Miyasaka, Shigeki; Tajima, Setsuko; Niimi, Yasuhiro; Kobayashi, Kensuke

2018-05-01

Thin layers of Bi2Sr2CaCu2O8+δ (Bi2212) were fabricated using the mechanical exfoliation technique. Good electrical contacts to the thin Bi2212 films with low contact resistance were realized by depositing Ag and Au electrodes onto the Bi2212 films and annealing them with an oxygen flow at 350 °C for 30 min. We observed cross-section images of the Bi2212 thin film device using a transmission electron microscope to characterize the diffusion of Ag and Au atoms into the Bi2212 thin film.

Antarctic Meteorite Newsletter, volume 8, number 1

NASA Technical Reports Server (NTRS)

1985-01-01

Preliminary descriptions and classifications of meteorites examined since the July 1984 newsletter are presented. Each macroscopic description summarizes features that were visible to the eye (with, at most, 50X magnification). Each thin section description represents features that were found in a survey-level examination of a polished thin section that was prepared from a small (usually extrior) chip of the meteorite. Classification is based on microscopic petrography and reconnaissance-level electron-probe microanalyses.

Computer program for thin-wire structures in a homogeneous conducting medium

NASA Technical Reports Server (NTRS)

Richmond, J. H.

1974-01-01

A computer program is presented for thin-wire antennas and scatters in a homogeneous conducting medium. The anaylsis is performed in the real or complex frequency domain. The program handles insulated and bare wires with finite conductivity and lumped loads. The output data includes the current distribution, impedance, radiation efficiency, gain, absorption cross section, scattering cross section, echo area and the polarization scattering matrix. The program uses sinusoidal bases and Galerkin's method.

Electrical and geochemical properties of tufa deposits as related to mineral composition in the South Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Gomaa, Mohamed M.; Abou El-Anwar, Esmat A.

2015-06-01

The geochemical, petrographical, and electrical properties of rocks are essential to the investigation of the properties of minerals. In this paper we will try to present a study of the A. C. electrical properties of carbonate rock samples and their relation to petrographical and geochemical properties. Samples were collected from four formations from the Bir Dungul area, in the South Western Desert, Egypt. The electrical properties of the samples were measured using a non-polarizing electrode, at room temperature (~28 °C), and at a relative atmospheric humidity of (~45%), in the frequency range from 42 Hz to 5 MHz. The changes in the electrical properties were argued to the change in mineral composition. Generally, the electrical properties of rocks are changed due to many factors e.g., grain size, mineral composition, grain shape and inter-granular relations between grains. The dielectric constant of samples decreases with frequency, and increases with conductor concentration. Also, the conductivity increases with an increase of continuous conductor paths between electrodes. The petrographical and geochemical studies reveal that the deposition of the tufa deposits occurred in shallow lakes accompanied by a high water table, an alkaline spring recharge and significant vegetation cover. Diagenetically, tufa deposits were subjected to early and late diagenesis. Petrography and geochemistry studies indicated that the area of tufa deposits was deposited under the control of bacterial activity. Geochemically, the Sr content indicates that the tufa deposits formed from dissolved bicarbonate under the control of microbes and bacterial activity.

Behaviour of thin-walled cold-formed steel members in eccentric compression

NASA Astrophysics Data System (ADS)

Ungureanu, Viorel; Kotełko, Maria; Borkowski, Łukasz; Grudziecki, Jan

2018-01-01

Thin-walled cold-formed steel structures are usually made of members of class 4 cross-sections. Since these sections are prematurely prone to local or distortional buckling and due to the fact they do not have a real post-elastic capacity, the failure at ultimate stage of those members, either in compression or bending, always occurs by forming a local plastic mechanism. The present paper investigates the evolution of the plastic mechanisms and the possibility to use them to characterise the ultimate strength of short thin-walled cold-formed steel members subjected to eccentric compression about minor axis, particularly for members with lipped channel cross-section. Five different types of plastic mechanisms for members in compression with different eccentricities are identified and examined on the basis of FE numerical simulations. Preliminary results of experimental validation of numerical results are presented. The research is based on previous studies and some new investigations of the authors.

Applications of Blue Light-curing Acrylic Resin to Forensic Sample Preparation and Microtomy.

PubMed

Groves, Ethan; Palenik, Christopher S

2016-03-01

This study discusses the results of an evaluation of a one-part blue light-curing acrylic resin for embedding trace evidence prior to the preparation of thin sections with a microtome. Through a comparison to several epoxy resins, the physical properties relevant to both trace evidence examination and analytical microscopy in general, including as viscosity, clarity, color, hardness, and cure speed, were explored. Finally, thin sections from paint samples embedded in this acrylic resin were evaluated to determine if, through smearing or impregnation, the resin contributed to the infrared spectra. The results of this study show that blue light-curing acrylic resins provide the desired properties of an embedding medium, generate high-quality thin sections, and can significantly simplify the preparation of paint chips, fibers and a multitude of other types of microscopic samples in the forensic trace evidence laboratory. © 2015 American Academy of Forensic Sciences.

Automated thin-film analyses of anhydrous interplanetary dust particles in the analytical electron microscope

NASA Technical Reports Server (NTRS)

Bradley, J. P.; Germani, M. S.; Brownlee, D. E.

1989-01-01

An AEM apparatus equipped with digital beam control has obtained quantitative point-count analyses of thin sections taken from eight anhydrous chondritic interplanetary dust particles (IDPs); between 200 and 500 X-ray analyses were collected from each thin section and analyzed for Mg, Al, Si, S, Ca, Cr, Mn, Fe, and Ni. Two types of anhydrous chondritic aggregates were observed in the eight IDPs: one highly porous, the other less so. The eight anhydrous IDPs are characterizable as mixtures of fine- and coarse-grained aggregates, large mineral grains, glass, and carbonaceous materials. Their elemental concentrations follow those of solar abundances, suggesting that they are unperturbed by aqueous alteration.

Antarctic Meteorite Newsletter, volume 7, number 2: Sample requests and allocations

NASA Technical Reports Server (NTRS)

1984-01-01

A listing of meteorites found in Antarctica is provided, along with a description of some of the less common types. Petrographic and physical descriptions, weight data, and locations of the less common meteorites are given.

Learning and researching in the classroom

NASA Astrophysics Data System (ADS)

Playa, E.; Travé, A.

2009-04-01

A new method in the course "Carbonate rocks diagenesis" has been tested. This is an optional course in the year 4 of a four year degree in Geology (University of Barcelona, Spain). The number of students in the course is generally reduced (less than ten), and duration of the course is 3 one-hour lecture and 1 three-hour practical per week during 5 weeks. This course has been selected to test a new learning method because is given in the last year of the undergraduate degree and also because the number of students is low, thus achieving a great degree of motivation of the students and favouring the communication in the classroom. The new model implies a general change in the development of the course: students will be trained in scientific research, working in group and using available analytical techniques. Nevertheless, this method does not invalidate the pre-existing educational resources; both new and classic teaching materials coexist in the course. Traditionally, the course was divided in lectures and practical work. The practical work is done on rock specimens and on thin sections using the petrological microscope, which is essentially invariable every course, and which is related with the theoretical concepts explained in the corresponding lecture. The students describe and interpret the material in a "passive" way, only with minor student-teacher feed-back when specific questions are asked by the student. The real learning in Sciences is not learning of isolate subjects, but to understand the relationships between all these subjects. Therefore, the student must learn science and how to do science. In the new tested method, the students carry out by themselves a scientific research project from a basic material provided by the teacher. This research work, which is done along the 5 weeks course, consists on a single project developed from all the students as a single group, thus observing the evolution in the student's knowledge and opening a continuous feed-back in the student-student and student-teacher relationships. This proposal implies that the lectures and practicals of the course must be reorganized and adapted. The research work is presented during the first day of the course, including a general presentation of the geological setting and the main problem to solve. The research work is developed during the entire course in the classroom, and concluded at the end of the course. In the first part of the research (2-3 weeks), the students will describe a set of samples (hand rocks and thin sections) in order to define the petrographic characteristic (mainly focused in diagenetic processes affecting carbonate rocks and the stages of cementation and its relationships with the fracturation events). The samples are distributed among the students and the description of the samples is individual; students must reach and agreement about the common petrographic features of the rocks and establish a global diagenetic sequence for the studied material. The second part of the research consists on the application of advanced instrumentation and analytical techniques, available in the University of Barcelona, such as cathodoluminescence microscope, microprobe and carbona and oxygen isotope analyses. The obtained results must be processed and comparison with published data by means of bibliographic research should be done by the students out of the classroom. The last part of the research project includes a complete and collective analysis of the results, elaboration of an individual final report (which should take into account the conclusions arrived by the entire group) and an oral presentation of the main results in the classroom. During the development of the work, the teacher acts as a tutor and mediator in the discussions, not only as a transmissor of knowledge. The new proposal differs from the classical undergraduate research projects developed in other courses, which are carried out outside the classroom, and therefore, without the continuous support of the teacher. The degree of satisfaction of the students at the end of the course is great, as evidenced in the opinion polls; students perceive that their individual effort is manifested in a final and global work. Additionally, implantation of this method in the classroom has been revealed as a good system of developing future researchers as several students having done this research method in the course of "Carbonate rocks diagenesis" have continued their scientific career. Acknowledgements The present work was supported by the Grup d'Innovació Docent del Departament de Geoquímica, Petrologia i Prospecció Geològica (University of Barcelona).

Cross-sectional TEM specimen preparation for W/B{sub 4}C multilayer sample using FIB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mondal, Puspen, E-mail: puspen@rrcat.gov.in; Pradhan, P. C.; Tiwari, Pragya

2016-05-23

A recent emergence of a cross-beam scanning electron microscopy (SEM)/focused-ion-beam (FIB) system have given choice to fabricate cross-sectional transmission electron microscopy (TEM) specimen of thin film multilayer sample. A 300 layer pair thin film multilayer sample of W/B{sub 4}C was used to demonstrate the specimen lift-out technique in very short time as compared to conventional cross-sectional sample preparation technique. To get large area electron transparent sample, sample prepared by FIB is followed by Ar{sup +} ion polishing at 2 kV with grazing incident. The prepared cross-sectional sample was characterized by transmission electron microscope.

Extraction efficiency and implications for absolute quantitation of propranolol in mouse brain, liver and kidney thin tissue sections using droplet-based liquid microjunction surface sampling-HPLC ESI-MS/MS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kertesz, Vilmos; Weiskittel, Taylor M.; Vavek, Marissa

Currently, absolute quantitation aspects of droplet-based surface sampling for thin tissue analysis using a fully automated autosampler/HPLC-ESI-MS/MS system are not fully evaluated. Knowledge of extraction efficiency and its reproducibility is required to judge the potential of the method for absolute quantitation of analytes from thin tissue sections. Methods: Adjacent thin tissue sections of propranolol dosed mouse brain (10- μm-thick), kidney (10- μm-thick) and liver (8-, 10-, 16- and 24- μm-thick) were obtained. Absolute concentration of propranolol was determined in tissue punches from serial sections using standard bulk tissue extraction protocols and subsequent HPLC separations and tandem mass spectrometric analysis. Thesemore » values were used to determine propranolol extraction efficiency from the tissues with the droplet-based surface sampling approach. Results: Extraction efficiency of propranolol using 10- μm-thick brain, kidney and liver thin tissues using droplet-based surface sampling varied between ~45-63%. Extraction efficiency decreased from ~65% to ~36% with liver thickness increasing from 8 μm to 24 μm. Randomly selecting half of the samples as standards, precision and accuracy of propranolol concentrations obtained for the other half of samples as quality control metrics were determined. Resulting precision ( ±15%) and accuracy ( ±3%) values, respectively, were within acceptable limits. In conclusion, comparative quantitation of adjacent mouse thin tissue sections of different organs and of various thicknesses by droplet-based surface sampling and by bulk extraction of tissue punches showed that extraction efficiency was incomplete using the former method, and that it depended on the organ and tissue thickness. However, once extraction efficiency was determined and applied, the droplet-based approach provided the required quantitation accuracy and precision for assay validations. Furthermore, this means that once the extraction efficiency was calibrated for a given tissue type and drug, the droplet-based approach provides a non-labor intensive and high-throughput means to acquire spatially resolved quantitative analysis of multiple samples of the same type.« less

Extraction efficiency and implications for absolute quantitation of propranolol in mouse brain, liver and kidney thin tissue sections using droplet-based liquid microjunction surface sampling-HPLC ESI-MS/MS

DOE PAGES

Kertesz, Vilmos; Weiskittel, Taylor M.; Vavek, Marissa; ...

2016-06-22

Currently, absolute quantitation aspects of droplet-based surface sampling for thin tissue analysis using a fully automated autosampler/HPLC-ESI-MS/MS system are not fully evaluated. Knowledge of extraction efficiency and its reproducibility is required to judge the potential of the method for absolute quantitation of analytes from thin tissue sections. Methods: Adjacent thin tissue sections of propranolol dosed mouse brain (10- μm-thick), kidney (10- μm-thick) and liver (8-, 10-, 16- and 24- μm-thick) were obtained. Absolute concentration of propranolol was determined in tissue punches from serial sections using standard bulk tissue extraction protocols and subsequent HPLC separations and tandem mass spectrometric analysis. Thesemore » values were used to determine propranolol extraction efficiency from the tissues with the droplet-based surface sampling approach. Results: Extraction efficiency of propranolol using 10- μm-thick brain, kidney and liver thin tissues using droplet-based surface sampling varied between ~45-63%. Extraction efficiency decreased from ~65% to ~36% with liver thickness increasing from 8 μm to 24 μm. Randomly selecting half of the samples as standards, precision and accuracy of propranolol concentrations obtained for the other half of samples as quality control metrics were determined. Resulting precision ( ±15%) and accuracy ( ±3%) values, respectively, were within acceptable limits. In conclusion, comparative quantitation of adjacent mouse thin tissue sections of different organs and of various thicknesses by droplet-based surface sampling and by bulk extraction of tissue punches showed that extraction efficiency was incomplete using the former method, and that it depended on the organ and tissue thickness. However, once extraction efficiency was determined and applied, the droplet-based approach provided the required quantitation accuracy and precision for assay validations. Furthermore, this means that once the extraction efficiency was calibrated for a given tissue type and drug, the droplet-based approach provides a non-labor intensive and high-throughput means to acquire spatially resolved quantitative analysis of multiple samples of the same type.« less

Better Finite-Element Analysis of Composite Shell Structures

NASA Technical Reports Server (NTRS)

Clarke, Gregory

2007-01-01

A computer program implements a finite-element-based method of predicting the deformations of thin aerospace structures made of isotropic materials or anisotropic fiber-reinforced composite materials. The technique and corresponding software are applicable to thin shell structures in general and are particularly useful for analysis of thin beamlike members having open cross-sections (e.g. I-beams and C-channels) in which significant warping can occur.

Static and free-vibrational response of semi-circular graphite-epoxy frames with thin-walled open sections

NASA Technical Reports Server (NTRS)

Collins, J. Scott; Johnson, Eric R.

1989-01-01

Experiments were conducted to measure the three-dimensional static and free vibrational response of two graphite-epoxy, thin-walled, open section frames. The frames are semi-circular with a radius of three feet, and one specimen has an I cross section and the other has a channel cross section. The flexibility influence coefficients were measured in static tests for loads applied at midspan with the ends of the specimens clamped. Natural frequencies and modes were determined from vibrational tests for free and clamped end conditions. The experimental data is used to evaluate a new finite element which was developed specifically for the analysis of curved, thin-walled structures. The formulation of the element is based on a Vlasov-type, thin-walled, curved beam theory. The predictions from the finite element program generally correlated well with the experimental data for the symmetric I-specimen. Discrepancies in some of the data were found to be due to flexibility in the clamped end conditions. With respect to the data for the channel specimen, the correlation was less satisfactory. The finite element analysis predicted the out-of-plane response of the channel specimen reasonably well, but large discrepancies occurred between the predicted in-plane response and the experimental data. The analysis predicted a much more compliant in-plane response than was observed in the experiments.

Sedimentology, Petrography and Microfacies of the Paleogene Carbonate Sequence - Yaxcopoil-1 Borehole (Chicxulub, Yucatan)

NASA Astrophysics Data System (ADS)

Escobar-Sanchez, E.; Fucugauchi, J. U.

2013-05-01

Chicxulub crater is one the three largest known impact craters on Earth, formed 66 Ma-old, with multi-ring basin morphology. Crater is located in northwestern Yucatan, southern Gulf of Mexico, with rim diameter of 200 km and crater center at Chicxulub Perto in the coastline. It is buried beneath the carbonate and evaporitic Cenozoic sequence. Study of the structure requires geophysics and drilling, with several boreholes drilled in the peninsula. The Yaxcopoil-1 borehole was drilled south of Merida, about 62 km from center, as part of the Chicxulub Scientific Drilling Program. One of the main objectives was to determine the role of the Chicxulub impact event in the K/Pg mass extinction and boundary events. We present a sedimentological and petrological study of the carbonate sequence in the interval from 404 m to 792 m overlying the K/Pg boundary. The well reached a depth of 1510.6 m. In this interval, we identified twelve units marked by different lithological and sedimentological changes, and supplemented by thin section analysis. Facies are composed mainly of marls, argillaceous, limestones, dolomitized limestones, calcareous breccias and calcarenites with shales thin beds. From the microfacies study we observed several major changes in the microfacies. From bottom of the sequence several textural changes cyclic from mudstone to bioclastic planktic foraminiferal wackestone, bioclastic packstone and some bioclastic grainstone. Two textures dominated in the calcareous sequence: bioclastic wackestone and packstone microfacies. From the microfacies study, we derived inferences on stable environmental conditions. We observed benthic and planktic foraminiferal layers. The benthic foraminifera strongly depend on environmental parameters, such as nutrient supply or oxygenation of the sea bottom water in the Paleocene and Eocene. Changes suggest occurrence of a progradational event, with a relative increase in sea level very slowly, with the sediment enough to overcome the elevation. In the last meters of Unit 2 (778-772 m), a series of thin layers of marl and calcareous shale interbedded with wackestone are interpreted as a transgressive event. In the first few meters of Unit 3 provides greater energy currents causing variations in the grain size. Petrographic observations show that planktonic and benthic facies are arranged as intermittent flows in parts of the unit, which points to flow currents. Predominance of coarse-grained facies rich in carbonates possibly indicates a prograding event into deep areas. In the sequence several possible changes in sea level are recorded, especially from Unit 5 to 8 Unit, where a possible limit between the Paleocene and Eocene is located between Unit 6 and Unit 7, at about 660 m. Biostratigraphy was obtained by zones corresponding to P4 and P5. In Unit 8 contains the first record of turbidite or storm deposits outer shelf environments that could be related to platform progradation. The Paleocene-Eocene thermal maximum represents a period of global warming and sea level rise. The sedimentological and micropaleontological changes may be correlated with the faunal turnover in the Gulf of Mexico, providing a complementary tool for biostratigraphic inferences.

Flexural-torsional vibration of a tapered C-section beam

NASA Astrophysics Data System (ADS)

Dennis, Scott T.; Jones, Keith W.

2017-04-01

Previous studies have shown that numerical models of tapered thin-walled C-section beams based on a stepped or piecewise prismatic beam approximation are inaccurate regardless of the number of elements assumed in the discretization. Andrade recently addressed this problem by extending Vlasov beam theory to a tapered geometry resulting in new terms that vanish for the uniform beam. (See One-Dimensional Models for the Spatial Behaviour of Tapered Thin-Walled Bars with Open Cross-Sections: Static, Dynamic and Buckling Analyses, PhD Thesis, University of Coimbra, Portugal, 2012, https://estudogeral.sib.uc.pt) In this paper, we model the coupled bending-twisting vibration of a cantilevered tapered thin-walled C-section using a Galerkin approximation of Andrade's beam equations resulting in an 8-degree-of-freedom beam element. Experimental natural frequencies and mode shapes for 3 prismatic and 2 tapered channel beams are compared to model predictions. In addition, comparisons are made to detailed shell finite element models and exact solutions for the uniform beams to confirm the validity of the approach. Comparisons to the incorrect stepped model are also presented.

Multi-photon vertical cross-sectional imaging with a dynamically-balanced thin-film PZT z-axis microactuator.

PubMed

Choi, Jongsoo; Duan, Xiyu; Li, Haijun; Wang, Thomas D; Oldham, Kenn R

2017-10-01

Use of a thin-film piezoelectric microactuator for axial scanning during multi-photon vertical cross-sectional imaging is described. The actuator uses thin-film lead-zirconate-titanate (PZT) to generate upward displacement of a central mirror platform, micro-machined from a silicon-on-insulator (SOI) wafer to dimensions compatible with endoscopic imaging instruments. Device modeling in this paper focuses on existence of frequencies near device resonance producing vertical motion with minimal off-axis tilt even in the presence of multiple vibration modes and non-uniformity in fabrication outcomes. Operation near rear resonance permits large stroke lengths at low voltages relative to other vertical microactuators. Highly uniform vertical motion of the mirror platform is a key requirement for vertical cross-sectional imaging in the remote scan architecture being used for multi-photon instrument prototyping. The stage is installed in a benchtop testbed in combination with an electrostatic mirror that performs in-plane scanning. Vertical sectional images are acquired from 15 μm diameter beads and excised mouse colon tissue.

Thin bonded P.C.C. resurfacing : final report.

DOT National Transportation Integrated Search

1982-06-01

After the successful experimentation in Iowa with thin-bonded concrete overlays as an alternative to bituminous overlay, the Louisiana DOTD decided to resurface a short section of US 61, north of Baton Rouge, using this technique during April 1981. T...

Differentiating Metamorphic Events in a Polymetamorphic Terrane using Zr-in-Ttn thermometry and Titanite U-Pb Geochronology

NASA Astrophysics Data System (ADS)

Kenney, M.; Roeske, S.; Mulcahy, S. R.; Cottle, J. M.; Coble, M. A.

2016-12-01

In polymetamorphic terranes, it is problematic to link ages from geochronometers to metamorphic fabrics and, therefore, to a specific deformation event(s). It is necessary to analyze a mineral which may preserve multiple age domains. Titanite has been shown to retain multiple age and elemental domains in single grains through high-grade metamorphism. In this study, titanite U-Pb geochronology is used to examine whether ages are thermally reset along a sample transect towards a mylonitic shear zone in NW Argentina. This work also seeks to understand the conditions under which titanite resists resetting. A combination of petrographic and electron microprobe analyses reveal the textures and compositional domains in titanite, garnet, and hornblende. Titanite are elongate, wrapped by the mylonitic fabric, and have patchy elemental zoning. Garnet has distinct cores with prograde zoning and thin rims, which appear to be in equilibrium with the fabric defining minerals. Hornblende has inclusion rich cores and thin overgrowth rims in equilibrium with the fabric defining minerals. In-situ U-Pb and trace element data was collected in titanite from four samples, which all preserve lower-intercept ages between 900Ma and 1.0Ga. We observed no correlation between age and elemental domains; these domains correlate with Al and Nb variations. Zr-in-titanite temperatures preserve upper amphibolite facies conditions, 660ºC-710ºC. Given these results, we conclude that titanite U-Pb ages and temperatures reflect original Grenville metamorphism. 40Ar/39Ar hornblende cooling ages, of 515 Ma, suggested titanite may be reset near the shear zone but overprinting P-T of 560ºC and 0.8 GPa, fluid infiltration, and deformation did not cause significant Pb loss. Overprinting conditions and cooling ages suggest that rims of garnet and hornblende correlate to Paleozoic metamorphism, while textural evidence and titanite ages suggest garnet and hornblende cores grew during the Proterozoic.

Combining satellite image data and field observations to characterize fresh-water carbonates in Kurkur Oasis, Southern Egypt

NASA Astrophysics Data System (ADS)

Gaber, Ahmed; Khalaf, Fikry; Bastawisy, Mohamed; El-Baz, Farouk

2018-03-01

Several fresh-water carbonate deposits (tufa and travertine) were formed at different elevations within the Kurkur paleolake, 50 km west of Aswan, Egypt. Such paleolake was unique and confined in sag between the cuesta and the capping platform of Sin El-Kaddabaa Plateau. This work aims at integrating the remote sensing data together with the chemical and petrographic analyses to map and characterize these tufa and travertine deposits to define their paleo-depositional environment. A DEM with 2.5 m spatial resolution was generated from two ALOS/PRISM images to show geomorphological and hydrological parameters. In addition, full-polarimetric SAR data were used to investigate the scattering response of these tufa and travertine deposits. These deposits show a volume scattering response, with an increase in the pedestal height of the co- and cross-polarized signatures. The tufa and travertine deposits range from Pleistocene (older upper level) to Recent (younger lower level). The young tufa is hard, light brown porous and thinly-laminated, while the old tufa is generally coarse crystalline and consists of columnar pseudo denderitic calcite crystals. The travertine displays a stromatolitic fabric, where thin dark micritic algal laminae alternate with relatively thick calcitic bands (∼1 cm). Conducted XRD and chemical analyses reveal that these tufa and travertine are entirely composed of low magnesium calcite, with traces of quartz (<2%). Moreover, the δ13C and δ18O values suggest that the old tufa have been developed during warm pluvial periods, while the younger ones were precipitated in drier periods. Two hypotheses were introduced to explain the changes in the hydrological regime of Kurkur paleolake; the first proposes a hydrological breaching due to water overflow on the lake's low periphery areas that led to their desiccation (where the tufa and travertine were deposited) and the second is the possible integration into the regional drainage networks of the area presently occupied by Lake Nasser.

Origin and diagenetic evolution of gypsum and microbialitic carbonates in the Late Sag of the Namibe Basin (SW Angola)

NASA Astrophysics Data System (ADS)

Laurent, Gindre-Chanu; Edoardo, Perri; Ian, Sharp R.; Peacock, D. C. P.; Roger, Swart; Ragnar, Poulsen; Hercinda, Ferreira; Vladimir, Machado

2016-08-01

Ephemeral evaporitic conditions developed within the uppermost part of the transgressive Late Sag sequence in the Namibe Basin (SW Angola), leading to the formation of extensive centimetre- to metre-thick sulphate-bearing deposits and correlative microbialitic carbonates rich in pseudomorphs after evaporite crystals. The onshore pre-salt beds examined in this study are located up to 25 m underneath the major mid-Aptian evaporitic succession, which is typified at the outcrop by gypsiferous Bambata Formation and in the subsurface by the halite-dominated Loeme Formation. Carbonate-evaporite cycles mostly occur at the top of metre-thick regressive parasequences, which progressively onlap and overstep landward the former faulted (rift) topography, or fill major pre-salt palaeo-valleys. The sulphate beds are made up of alabastrine gypsum associated with embedded botryoidal nodules, dissolution-related gypsum breccia, and are cross-cut by thin satin-spar gypsum veins. Nodular and fine-grained fabrics are interpreted as being diagenetic gypsum deposits resulting from the dissolution and recrystallisation of former depositional subaqueous sulphates, whereas gypsum veins and breccia result from telogenetic processes. The carbonates display a broader diversity of facies, characterised by rapid lateral variations along strike. Thin dolomitic and calcitic bacterial-mediated filamentous microbialitic boundstones enclose a broad variety of evaporite pseudomorphs and can pass laterally over a few metres into sulphate beds. Dissolution-related depositional breccias are also common and indicate early dissolution of former evaporite layers embedded within the microbialites. Sulphate and carbonate units are interpreted as being concomitantly deposited along a tide-dominated coastal supra- to intertidal- sabkha and constitute high-frequency hypersaline precursor events, prior to the accumulation of the giant saline mid-Aptian Bambata and Loeme Formations. Petrographic and geochemical analyses reveal successive dissolution, recrystallisation and cementation phases that occurred during burial, uplift and exhumation, implying a complex diagenetic evolution of both gypsum and carbonates, influenced by pore fluids of diverse composition which distinctly varied from meso- to telogenetic domains.

Nanoscale size effects on the mechanical properties of platinum thin films and cross-sectional grain morphology

NASA Astrophysics Data System (ADS)

Abbas, K.; Alaie, S.; Ghasemi Baboly, M.; Elahi, M. M. M.; Anjum, D. H.; Chaieb, S.; Leseman, Z. C.

2016-01-01

The mechanical behavior of polycrystalline Pt thin films is reported for thicknesses of 75 nm, 100 nm, 250 nm, and 400 nm. These thicknesses correspond to transitions between nanocrystalline grain morphology types as found in TEM studies. Thinner samples display a brittle behavior, but as thickness increases the grain morphology evolves, leading to a ductile behavior. During evolution of the morphology, dramatic differences in elastic moduli (105-160 GPa) and strengths (560-1700 MPa) are recorded and explained by the variable morphology. This work suggests that in addition to the in-plane grain size of thin films, the transitions in cross-sectional morphologies of the Pt films significantly affect their mechanical behavior.

Quality response of even-aged 80-year-old white oak trees after thinning

Treesearch

David L. Sonderman

1984-01-01

Stem defects were studied over an 18-year period to determine the effect of thinning intensity on quality development of 80-year-old white oak trees. Seventy-nine white oak trees from a thinning study in Kentucky were analyzed from stereo photographs taken in 1960 and 1978. Stem-related defects were measured on the butt 8-foot and second 8-foot sections of each tree....

Normal Modes of Vibration of the PHALANX Gun

DTIC Science & Technology

1993-06-01

Clamps Bricks, Thin Shells, Rigid Elements Mid-Barrel Clamps Bricks, Rigid Elements Barrels Beams with tubular cross-section Stub Rotor Bricks, Thin...Shells Rotor Bricks Needle Bearing Bricks, Springs Casing Thin Shells Thrust Bearing Bricks, Springs Recoil Adapters Bricks, Rigid Elements, Springs... rigid elements were used to connect the barrels to the clamps and stub rotor and the recoil adapter springs to 48 the gun body. "End release codes

Effect of thinning on growth and potential quality of young white oak crop trees

Treesearch

Martin E. Dale; David L. Sonderman

1984-01-01

Relative change in several types of stem defects were studied over a 16-year period to determine the effect of thinning intensity on the development of tree quality. We studied quality changes on sample white oak crop trees that were selected from five density levels created in a 1961 thinning. Branch-related and other stem defects on the butt 16-foot section were...

Measurement of fragmentation cross sections of 12C ions on a thin gold target with the FIRST apparatus

NASA Astrophysics Data System (ADS)

Toppi, M.; Abou-Haidar, Z.; Agodi, C.; Alvarez, M. A. G.; Aumann, T.; Balestra, F.; Battistoni, G.; Bocci, A.; Böhlen, T. T.; Boudard, A.; Brunetti, A.; Carpinelli, M.; Cirio, R.; Cirrone, G. A. P.; Cortes-Giraldo, M. A.; Cuttone, G.; de Napoli, M.; Durante, M.; Fernández-García, J. P.; Finck, Ch.; Golosio, B.; Iarocci, E.; Iazzi, F.; Ickert, G.; Introzzi, R.; Juliani, D.; Krimmer, J.; Kummali, A. H.; Kurz, N.; Labalme, M.; Leifels, Y.; Le Fèvre, A.; Leray, S.; Marchetto, F.; Monaco, V.; Morone, M. C.; Nicolosi, D.; Oliva, P.; Paoloni, A.; Piersanti, L.; Pleskac, R.; Randazzo, N.; Rescigno, R.; Romano, F.; Rossi, D.; Rosso, V.; Rousseau, M.; Sacchi, R.; Sala, P.; Salvador, S.; Sarti, A.; Scheidenberger, C.; Schuy, C.; Sciubba, A.; Sfienti, C.; Simon, H.; Sipala, V.; Spiriti, E.; Tropea, S.; Vanstalle, M.; Younis, H.; Patera, V.; FIRST Collaboration

2016-06-01

A detailed knowledge of the light ions interaction processes with matter is of great interest in basic and applied physics. As an example, particle therapy and space radioprotection require highly accurate fragmentation cross-section measurements to develop shielding materials and estimate acute and late health risks for manned missions in space and for treatment planning in particle therapy. The Fragmentation of Ions Relevant for Space and Therapy experiment at the Helmholtz Center for Heavy Ion research (GSI) was designed and built by an international collaboration from France, Germany, Italy, and Spain for studying the collisions of a 12C ion beam with thin targets. The collaboration's main purpose is to provide the double-differential cross-section measurement of carbon-ion fragmentation at energies that are relevant for both tumor therapy and space radiation protection applications. Fragmentation cross sections of light ions impinging on a wide range of thin targets are also essential to validate the nuclear models implemented in MC simulations that, in such an energy range, fail to reproduce the data with the required accuracy. This paper presents the single differential carbon-ion fragmentation cross sections on a thin gold target, measured as a function of the fragment angle and kinetic energy in the forward angular region (θ ≲6° ), aiming to provide useful data for the benchmarking of the simulation softwares used in light ions fragmentation applications. The 12C ions used in the measurement were accelerated at the energy of 400 MeV/nucleon by the SIS (heavy ion synchrotron) GSI facility.

Thin bonded P.C.C. resurfacing : interim report No. 1.

DOT National Transportation Integrated Search

1982-06-01

After the successful experimentation in Iowa with thin-bonded concrete overlays as an alternative to bituminous overlay, the Louisiana DOTD decided to resurface a short section of US 61, north of Baton Rouge, using this technique during April 1981. T...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buck, E.C.; Dietz, N.L.; Bates, J.K.

Uranium contaminated soils from the Fernald Operation Site, Ohio, have been examined by a combination of optical microscopy, scanning electron microscopy with backscattered electron detection (SEM/BSE), and analytical electron microscopy (AEM). A method is described for preparing of transmission electron microscopy (TEM) thin sections by ultramicrotomy. By using these thin sections, SEM and TEM images can be compared directly. Uranium was found in iron oxides, silicates (soddyite), phosphates (autunites), and fluorite. Little uranium was associated with clays. The distribution of uranium phases was found to be inhomogeneous at the microscopic level.

Analysis of asymmetric property with DC bias current on thin-film magnetoimpedance element

NASA Astrophysics Data System (ADS)

Kikuchi, Hiroaki; Sumida, Chihiro

2018-05-01

We theoretically analyzed the magnetoimpedance profile of a thin-film element with a DC bias current using the bias susceptibility theory and Maxwell's equations. Although the analysis model predicts that an element with a rectangular cross section shows symmetric impedance property with respect to the Z-axis with DC bias current, the experimental results showed asymmetric properties. Taking the shape imbalance and trapezoidal cross section of the element into account, we explained the asymmetric impedance properties qualitatively.

Evaluation of cores from Jefferson Highway near Airline Highway : technical assistance report 16-03TA-C.

DOT National Transportation Integrated Search

2016-09-01

This technical assistance report documents the investigation conducted by the Louisiana Transportation Research Center (LTRC) of the cored concrete from Westbound Jefferson Highway near Airline Highway in Baton Rouge, LA. The petrographic analysis sh...

Hidden Ice Worlds - Pleistocene glacigenic deposits in Essex, England. Application of the novel systematic approach to thin-section description.

NASA Astrophysics Data System (ADS)

Leszczynska, Karolina; Boreham, Julie; Boreham, Steve

2013-04-01

In the 'Hidden Ice Worlds' research project a novel systematic approach for thin-section description (Leszczynska et al., 2011) is applied to analyse the internal structure of 8 m thick periglacially disturbed sequence from the Royal Oak Pit - a small disused quarry in East Anglia, Essex, east of Chelmsford, near Danbury. Danbury Hill is situated on the south-eastern margin of the Elsterian (Anglian) till sheet. This area was glaciated only once, during the Pleistocene, Elsterian (Anglian) glaciation (480-420 ka BP), however two local ice-sheet margin fluctuations are envisaged (inter alia Turner, 1970 and others). The stratigraphical sequence of the Royal Oak Pit comprises: massive gravel, arranged in sheets, overlain by fine silty-clay and silty-sand with ripple marks and planar cross beds, overlain by a 50 cm thick unit of massive gravel gradually changing into periglacially disturbed silty-clayey-gravel with the bottom 50 cm of fine laminated silty clay. This sequence is situated on the lee side of Danbury Hill, at over 50 m OD. This is an atypical location for the periglacially disturbed deposits of such a substantial thickness (up to 8 m), which usually occur in the lower areas. The deposits at this site were investigated at a macro-scale using field-section logging, ground penetrating radar survey, clast lithology, clay mineralogy analysis and loss-on-ignition and at a micro-scale using thin-section analysis. There are two main aims of the project presented: • To describe the genesis and to discern the main processes associated with the formation of the unusually thick periglacially disturbed unit at the Danbury Hill slope and • To test the novel, tree-based, systematic approach as a guiding tool for thin for thin-section description of Quaternary deposits (Leszczynska et al., 2011). The results of the micromorphological analyses of the deposits from the Royal Oak Pit allow a new hypothesis for the origin of the sequence to be put forward. The main process responsible for the evolution of the deposits consist of multiple phases of freezing and thawing of the deposit and associated physical reworking, subsequent to Elsterian (Anglian). Inversion of the topography is proposed as a necessary condition for the formation and preservation of the periglacially disturbed sequence on hill slope at such elevated location. The novel systematic approach proved to be a useful tool in guiding the thin-section description, regardless of the type of the deposit and the aim of the research. Reference: Leszczynska, K., Boreham, J. and Boreham, S., 2011. A novel methodological approach for thin-section description and its application to periglacially disturbed Pleistocene deposits from Danbury, Essex, UK. Netherlands Journal of Geosciences 90: 271-291. Turner, C., 1970. Middle Pleistocene deposits at Marks Tey, Essex. Philosophical Transactions of the Royal Society of London, series B 257: 373-440.

Multispectral Digital Image Analysis of Varved Sediments in Thin Sections

NASA Astrophysics Data System (ADS)

Jäger, K.; Rein, B.; Dietrich, S.

2006-12-01

An update of the recently developed method COMPONENTS (Rein, 2003, Rein & Jäger, subm.) for the discrimination of sediment components in thin sections is presented here. COMPONENTS uses a 6-band (multispectral) image analysis. To derive six-band spectral information of the sediments, thin sections are scanned with a digital camera mounted on a polarizing microscope. The thin sections are scanned twice, under polarized and under unpolarized plain light. During each run RGB images are acquired which are subsequently stacked to a six-band file. The first three bands (Blue=1, Green=2, Red=3) result from the spectral behaviour in the blue, green and red band with unpolarized light conditions, and the bands 4 to 6 (Blue=4, Green=5, Red=6) from the polarized light run. The next step is the discrimination of the sediment components by their transmission behaviour. Automatic classification algorithms broadly used in remote sensing applications cannot be used due to unavoidable variations of sediment particle or thin section thicknesses that change absolute grey values of the sediment components. Thus, we use an approach based on band ratios, also known as indices. By using band ratios, the grey values measured in different bands are normalized against each other and illumination variations (e.g. thickness variations) are eliminated. By combining specific ratios we are able to detect all seven major components in the investigated sediments (carbonates, diatoms, fine clastic material, plant rests, pyrite, quartz and resin). Then, the classification results (compositional maps) are validated. Although the automatic classification and the analogous classification show high concordances, some systematic errors could be identified. For example, the transition zone between the sediment and resin filled cracks is classified as fine clastic material and very coarse carbonates are partly classified as quartz because coarse carbonates can be very bright and spectra are partly saturated (grey value 255). With reduced illumination intensity "carbonate image pixels" get unsaturated and can be well distinguished from quartz grains. During the evaluation process we identify all falsely classified areas using neighbourhood matrices and reclassify them. Finally, we use filter techniques to derive downcore component frequencies from the classified thin section images for variable thick virtual samples. The filter conducts neighbourhood analyses. After filtering, each pixel of the filtered images carries the information about the frequency of any given component in a defined neighbourhood around (virtual sampling). References Rein, B. (2003) In-situ Reflektionsspektroskopie und digitale Bildanalyse Gewinnung hochauflösender Paläoumweltdaten mit fernerkundlichen Methoden, Habilitation Thesis, Univ. Mainz, 104 p. Jäger, K. and Rein, B. (2005): Identifying varve components using digital image analysis techniques. - in: Heidi Haas, Karl Ramseyer & Fritz Schlunegger (eds.): Sediment 2005 (18th-20th July 2005), Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften, 38, p. 81 Rein, B. and Jäger, K. (subm.) COMPONENTS - Sediment component detection in thin sections by multispectral digital image analysis. Sedimentology.

Chondrule formation, metamorphism, brecciation, an important new primary chondrule group, and the classification of chondrules

NASA Technical Reports Server (NTRS)

Sears, Derek W. G.; Shaoxiong, Huang; Benoit, Paul H.

1995-01-01

The recently proposed compositional classification scheme for meteoritic chondrules divides the chondrules into groups depending on the composition of their two major phases, olivine (or pyroxene) and the mesostasis, both of which are genetically important. The scheme is here applied to discussions of three topics: the petrographic classification of Roosevelt County 075 (the least-metamorphosed H chondrite known), brecciation (an extremely important and ubiquitous process probably experienced by greater than 40% of all unequilibrated ordinary chondrites), and the group A5 chondrules in the least metamorphosed ordinary chondrites which have many similarities to chondrules in the highly metamorphosed 'equilibrated' chondrites. Since composition provides insights into both primary formation properties of the chondruies and the effects of metamorphism on the entire assemblage it is possible to determine the petrographic type of RC075 as 3.1 with unique certainty. Similarly, the near scheme can be applied to individual chondrules without knowledge of the petrographic type of the host chondrite, which makes it especially suitable for studying breccias. Finally, the new scheme has revealed the existence of chondrules not identified by previous techniques and which appear to be extremely important. Like group A1 and A2 chondrules (but unlike group B1 chondrules) the primitive group A5 chondruies did not supercool during formation, but unlike group A1 and A2 chondrules (and like group B1 chondrules) they did not suffer volatile loss and reduction during formation. It is concluded that the compositional classification scheme provides important new insights into the formation and history of chondrules and chondrites which would be overlooked by previous schemes.

Geochemical evidence for mixing of three components in martian orthopyroxenite ALH 84001. [Abstract only

NASA Technical Reports Server (NTRS)

Mittlefehldt, D. W.; Lindstrom, M. M.

1994-01-01

ALH 84001, a ferroan martian orthopyroxenite, originally consisted of three petrographically defined components: a cumulus assemblage of orthopyroxene + chromite, a trapped melt assemblage of orthopyroxene(?) + chromite + maskelynite + apatite + augite +/- pyrite, and a metasomatic assemblage of carbonate +/- pyrite. We present the results of Instrumental Neutron Activation Analysis (INAA) study of five bulk samples of ALH 84001, combined with Scanning Ion Mass Spectrometer (SIMS) data on the orthopyroxene, in order to attempt to set limits on the geochemical characteristics of the latter two components, and therefore on the petrogenesis of ALH 84001. The INAA data support the petrographic observations, suggesting that there are at least three components in ALH 84001. We will assume that each of the three geochemically required components can be equated with one of the petrographically observed components. Both trapped melt and metasomatic components in ALH 84001 have higher Na than orthopyroxene based on compositions of maskelynite, apatite, and carbonate. For the metasomatic component, we will assume its Na content is that of carbonate, while for a trapped melt component, we will use a typical Na content inferred for martian meteorite parent melts, approximately 1 wt% Na2O. Under these assumptions, we can set limits on the Light Rare Earth Elements/Heavy Rare Earth Elements (LREE/HREE) ratios of the components, and use this information to compare the petrogenesis of ALH 84001 with other martian meteorites. The above calculations assume that the bulk samples are representative of different portions of ALH 84001. We will also evaluate the possible heterogeneous distribution of mineral phases in the bulk samples as the cause of compositional heterogeneity in our samples.

Evidence of Metasomatism in the Lowest Petrographic Types Inferred from A Na(-), K, Rich Rim Around A LEW 86018 (L3.1) Chondrule

NASA Technical Reports Server (NTRS)

Mishra, Ritesh Kumar; Marhas, Kuljeet Kaur; Simon, Justin I.; Ross, Daniel Kent

2015-01-01

Ordinary chondrites (OCs) represent the most abundant extraterrestrial materials and also record the widest range of alteration of primary, pristine minerals of early Solar system material available for study. Relatively few investigations, however, address: (1) the role of fluid alteration, and (2) the relationship between thermal metamorphism and metasomatism in OCs, issues that have been extensively studied in many other meteorite groups e.g., CV, CO, CR, and enstatite chondrites. Detailed elemental abundances profiles across individual chondrules, and mineralogical studies of Lewis Hills (LEW) 86018 (L3.1), an unequilibrated ordinary chondrite (UOC) of low petrographic type of 3.1 returned from Antarctica, provide evidence of extensive alteration of primary minerals. Some chondrules have Na(-), K(-), rich rims surrounded by nepheline, albite, and sodalite-like Na(-), Cl(-), Al-rich secondary minerals in the near vicinity within the matrices. Although, limited evidences of low temperature (approximately 250 C) fluid-assisted alteration of primary minerals to phyllosilicates, ferroanolivine, magnetite, and scapolite have been reported in the lowest grades (less than 3.2) Semarkona (LL3.00) and Bishunpur (LL3.10), alkali-rich secondary mineralization has previously only been seen in higher grade greater than 3.4 UOCs. This preliminary result suggests highly localized metamorphism in UOCs and widens the range of alteration in UOCs and complicates classification of petrographic type and extent of thermal metamorphism or metasomatism. The work in progress will document the micro-textures, geochemistry (Ba, Ca, REE), and isotopic composition (oxygen, Al(-)- 26 Mg-26) of mineral phases in chondrules and adjoining objects to help us understand the formation scenario and delineate possible modes of metamorphism in UOCs.

Petrographic analysis of prehistoric ceramics from the Huagangshan site of Hualien City, eastern Taiwan

NASA Astrophysics Data System (ADS)

Liou, Y. S.; Yi-Chang, L.

2017-12-01

Numerous stone artifacts, ceramics, bone tools, metal objects, and etc., had been unearthed from the Huagangshan site of Hualien City, eastern Taiwan, during the excavations of 2008-2010 and 2012. Of particular importance is more than ten thousands of potsherds were discovered. A stratigraphic sequence spanning the late Early Neolithic (ca. 5000 BP) through to the prehistoric of Taiwan (300 BP) was excavated. This study focuses on potteries from the Late Neolithic (ca. 3500-2800 BP), owing to some ceramics exhibiting distinct stylistic motifs and morphological attributes were recognized to be not produced locally. Have these wares been brought to the area by exchange trade and/or by immigrants? Or had they been made by local potters through the imitation of exotic styles? It is still unclear and is one of the most important archaeological issues in eastern Taiwan. To clarify this subject, understanding the raw material compositions and sources, manufacturing techniques, and etc. are considered to be the best ways. Thus, 21 potsherds from excavations and 6 river sand samples near the site were studied by petrographic analysis. The results of petrographic study show that temper components in the potsherds are quartz, pyroxene, amphibole, plagioclase, sedimentary rock fragments (sandstone), igneous rock fragments (andesite), and metamorphic rock fragments (metasandstone, slate, schist), and the contents and proportions are different in these samples. Petrography shows that the ceramic have multiple origins. A ternary plot of rock fragments shows three compositional groups. This result discriminates two types of ceramics from the others and confirms those ceramics producing non-locally. However, one type of potsherds have local origins through they were recognized to be exotic ones.

Petrographic and reservoir features of Hauterivian (Lower Cretaceous) Shatlyk horizon in the Malay gas field, Amu-Darya basin, east Turkmenia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naz, H.; Ersan, A.

1996-08-01

Malay gas field in Amu-Darya basin, eastern Turkmenia, is located on the structural high that is on the Malay-Bagadzha arch north of the Repetek-Kelif structure zone. With 500 km{sup 2} areal coverage, 16 producing wells and 200 billion m{sup 3} estimated reserves, the field was discovered in 1978 and production began in 1987 from 2400-m-deep Hauterivian-age (Early Cretaceous) Shatlyk horizon. The Shatlyk elastic sequence shows various thickness up to 100 m in the Malay structural closure and is studied through E-log, core, petrographic data and reservoir characteristics. The Shatlyk consists of poorly indurated, reddish-brown and gray sandstones, and sandy graymore » shales. The overall sand-shale ratio increases up and the shales interleave between the sand packages. The reservoir sandstones are very fine to medium grained, moderately sorted, compositionally immature, subarkosic arenites. The framework grains include quartz, feldspar and volcanic lithic fragments. Quartz grains are monocrystalline in type and most are volcanic in origin. Feldspars consist of K- Feldspar and plagioclase. The orthoclases are affected by preferential alteration. The sandstones show high primary intergranular porosity and variations in permeability. Patch-like evaporate cement and the iron-rich grain coatings are reducing effects in permeability. The coats are pervasive in reddish-brown sandstones but are not observed in the gray sandstones. The evaporate cement is present in all the sandstone samples examined and, in places, follows the oxidation coats. The petrographic evidences and the regional facies studies suggest the deposition in intersection area from continental to marine nearshore deltaic environment.« less

Recrystallization and anatexis along the plutonic-volcanic contact of the Turkey Creek caldera, Arizona

USGS Publications Warehouse

du Bray, E.A.; Pallister, J.S.

1999-01-01

Unusual geologic and geochemical relations are preserved along the contact between intracaldera tuff and a resurgent intrusion within the 26.9 Ma Turkey Creek caldera of southeast Arizona. Thick intracaldera tuff is weakly argillically altered throughout, except in zones within several hundred meters of its contact with the resurgent intrusion, where the groundmass of the tuff has been variably converted to granophyre and unaltered sanidine phenocrysts are present. Dikes of similarly granophyric material originate at the tuff-resurgent intrusion contact and intrude overlying intracaldera megabreccia and tuff. Field relations indicate that the resurgent intrusion is a laccolith and that it caused local partial melting of adjacent intracaldera tuff. Geochemical and petrographic relations indicate that small volumes of partially melted intracaldera tuff assimilated and mixed with dacite of the resurgent intrusion along their contact, resulting in rocks that have petrographic and compositional characteristics transitional between those of tuff and dacite. Some of this variably contaminated, second-generation magma coalesced, was mobilized, and was intruded into overlying intracaldera rocks. Interpretation of the resurgent intrusion in the Turkey Creek and other calderas as intracaldera laccoliths suggests that intrusions of this type may be a common, but often unrecognized, feature of calderas. Development of granophyric and anatectic features such as those described here may be equally common in other calderas. The observations and previously undocumented processes described here can be applied to identification and interpretation of similarly enigmatic relations and rocks in other caldera systems. Integration of large-scale field mapping with detailed petrographic and chemical data has resulted in an understanding of otherwise intractable but petrologically important caldera-related features.

Carbon abundances, major element chemistry, and mineralogy of hydrated interplanetary dust particles

NASA Technical Reports Server (NTRS)

Keller, L. P.; Thomas, K. L.; Mckay, D. S.

1993-01-01

Hydrated interplanetary dust particles (IDP's) comprise a major fraction of the interplanetary dust particles collected in the stratosphere. While much is known about the mineralogy and chemistry of hydrated IDP's, little is known about the C abundance in this class of IDP's, the nature of the C-bearing phases, and how the C abundance is related to other physical properties of hydrated IDP's. Bulk compositional data (including C and O) for 11 hydrated IDP's that were subsequently examined by the transition electron microscopy (TEM) to determine their mineralogy and mineral chemistry are reported. Our analysis indicates that these hydrated IDP's are strongly enriched in C relative to the most C-rich meteorites. The average abundance of C in these hydrated IDP's is 4X CI chondrite values. The bulk compositions (including C and O) of 11 hydrated IDP's were determined by thin-window, energy-dispersive x ray (EDX) spectroscopy of the uncoated IDP's on Be substrates in the scanning electron microscopy (SEM). As a check on our C measurements, one of the IDP's (L2006H5) was embedded in glassy S, and microtome thin sections were prepared and placed onto Be substrates. Thin-film EDX analyses of multiple thin sections of L2006H5 show good agreement with the bulk value determined in the SEM. Following EDX analysis, the mineralogy and mineral chemistry of each IDP was determined by analyzing ultramicrotome thin sections in a TEM equipped with an EDX spectrometer.

Palladium, platinum, rhodium, iridium and ruthenium in chromite- rich rocks from the Samail ophiolite, Oman.

USGS Publications Warehouse

Page, N.J.; Pallister, J.S.; Brown, M.A.; Smewing, J.D.; Haffty, J.

1982-01-01

30 samples of chromitite and chromite-rich rocks from two stratigraphic sections, 250 km apart, through the basal ultramafic member of the Samail ophiolite were spectrographically analysed for platinum-group elements (PGE) and for Co, Cu, Ni and V. These data are reported as are Cr/(Cr + Al), Mg/(Mg + Fe) and wt.% TiO2 for most samples. The chromitite occurs as pods or lenses in rocks of mantle origin or as discontinuous layers at the base of the overlying cumulus sequence. PGE abundances in both sections are similar, with average contents in chromite-rich rocks: Pd 8 ppb, Pt 14 ppb, Rh 6 ppb, Ir 48 ppb and Ru 135 ppb. The PGE data, combined with major-element and petrographic data on the chromitite, suggest: 1) relatively larger Ir and Ru contents and highest total PGE in the middle part of each section; 2) PGE concentrations and ratios do not correlate with coexisting silicate and chromite abundances or chromite compositions; 3) Pd/PGE, on average, increases upward in each section; 4) Samail PGE concentrations, particularly Rh, Pt and Pd, are lower than the average values for chromite-rich rocks in stratiform intrusions. 2) suggests that PGEs occur in discrete alloy or sulphide phases rather than in the major oxides or silicates, and 4) suggests that chromite-rich rocks from the oceanic upper mantle are depleted in PGE with respect to chondrites. L.C.C.

Physical and chemical characteristics and development of the Changuinola peat deposit of northwestern Panama

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, A.D.; Raymond, R. Jr.; Thayer, G.

1987-08-01

A peat deposit occupying over 80 square kilometers, and averaging 8 meters in thickness, was discovered on the Caribbean coast of northwestern Panama near the town of Changuinola. This deposit occurs inland (behind) the present beach-barrier shoreline. It is thickest in the center and thins toward all edges (as if domed). The surface vegetation in the central regions consists primarily of ombrotrophic plants (especially sedges, grasses, Sphagnum, Sagittaria, and various scattered shrubs). Toward the edges, the deposit has a surface cover of more minerotrophic plants (such as swamp-forest trees, ferns, and palms). Petrographic/botanical analysis of the deposit with depth revealsmore » the presence of five peat types (swamp-forest, sedge-grass-fern, Sagittaria et al., Nymphaea et al., and Rhizophora). Typically peats of the thick, central portions of the deposit are very low in ash and sulfur (less than 2% ash and 0.3% sulfur). Ash contents tend to increase abruptly at the base and more gradually toward the edges of the deposit and sulfur contents increasing gradually toward the ocean and bay. Vertical and lateral variations in botanical, chemical, and physical properties of this deposit can be related to factors that have controlled: (1) the surrounding rocks and water chemistry; (2) the source vegetation; and (3) the environments in which these source ingredients were deposited. 3 refs., 10 figs.« less

Minor Elements in Nakhlite Pyroxenes: Does Cr Record Changes in REDOX Conditions during Crystallization?

NASA Technical Reports Server (NTRS)

McKay, G.; Schwandt, C.; Le, L.; Mikouchi, T.

2007-01-01

Nakhlites are olivine-bearing clinopyroxene cumulates. Based on petrographic characteristics, they may be divided into groups that cooled at different rates and may have been formed at different depths in a single flow. The order of cooling rate from slowest to fastest is NWA998

Model for dolomite formation in northwest Florida

USGS Publications Warehouse

Cooper, C.R.; Tindall, J.A.

1994-01-01

Petrographic methods are used to examine the nature of the Floridan post-Oligocene unconformity and diagenetic responses in the associated carbonate units. The study addresses the depositional environment and the character of sediments associated with the unconformity, types and timing of diagenetic changes, and mode of dolomitization for the Suwannee Limestone dolomites and basal Hawthorn Group dolosilts. The purpose of the study is to determine if the original texture of geologic materials is preserved more frequently in rocks deposited in a supratidal environment in the uppermost Floridan carbonates, to examine possible sources of magnesium for the dolomitization that has occurred in the Floridan aquifer, and to determine the chemical environment of dolomite formation. On the basis of lithology, the tri-county study area can be divided into two regions; one in which the uppermost Floridan carbonate is calcareous or locally silicified, and one in which the aquifer system is capped with dolomite. Lateral interfingering between the two regions is apparent, and it is inferred that the boundary between the limestone and dolomite represents a geochemical boundary between a mixed marine and freshwater environment and a subaerially exposed freshwater environment. Where dolomite has replaced the uppermost Suwannee Limestone, the dolomite is overlain by a thin unit of dolosilt. The predominant source of magnesium for the dolomitization that occurred in the study area is probably seawater. ?? 1994.

Mineralogical and chemical assessment of concrete damaged by the oxidation of sulfide-bearing aggregates: Importance of thaumasite formation on reaction mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodrigues, A.; Duchesne, J., E-mail: josee.duchesne@ggl.ulaval.ca; Fournier, B.

Damages in concrete containing sulfide-bearing aggregates were recently observed in the Trois-Rivieres area (Quebec, Canada), characterized by rapid deterioration within 3 to 5 years after construction. A petrographic examination of concrete core samples was carried out using a combination of tools including: stereomicroscopic evaluation, polarized light microscopy, scanning electron microscopy, X-ray diffraction and electron microprobe analysis. The aggregate used to produce concrete was an intrusive igneous rock with different metamorphism degrees and various proportions of sulfide minerals. In the rock, sulfide minerals were often surrounded by a thin layer of carbonate minerals (siderite). Secondary reaction products observed in the damagedmore » concrete include 'rust' mineral forms (e.g. ferric oxyhydroxides such as goethite, limonite (FeO (OH) nH{sub 2}O) and ferrihydrite), gypsum, ettringite and thaumasite. In the presence of water and oxygen, pyrrhotite oxidizes to form iron oxyhydroxides and sulphuric acid. The acid then reacts with the phases of the cement paste/aggregate and provokes the formation of sulfate minerals. Understanding both mechanisms, oxidation and internal sulfate attack, is important to be able to duplicate the damaging reaction in laboratory conditions, thus allowing the development of a performance test for evaluating the potential for deleterious expansion in concrete associated with sulfide-bearing aggregates.« less

FDTD modeling of thin impedance sheets

NASA Technical Reports Server (NTRS)

Luebbers, Raymond J.; Kunz, Karl S.

1991-01-01

Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. In this paper it is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods.

One-dimensional analysis of thin-walled beams with diaphragms and its application to optimization for stiffness reinforcement

NASA Astrophysics Data System (ADS)

Jung, Joon Hee; Jang, Gang-Won; Shin, Dongil; Kim, Yoon Young

2018-03-01

This paper presents a method to analyze thin-walled beams with quadrilateral cross sections reinforced with diaphragms using a one-dimensional higher-order beam theory. The effect of a diaphragm is reflected focusing on the increase of static stiffness. The deformations on the beam-interfacing boundary of a thin diaphragm are described by using deformation modes of the beam cross section while the deformations inside the diaphragm are approximated in the form of complete cubic polynomials. By using the principle of minimum potential energy, its stiffness that significantly affects distortional deformation of a thin-walled beam can be considered in the one-dimensional beam analysis. It is shown that the accuracy of the resulting one-dimensional analysis is comparable with that by a shell element based analysis. As a means to demonstrate the usefulness of the present approach for design, position optimization problems of diaphragms for stiffness reinforcement of an automotive side frame are solved.

Systematic approach to study of thinly and thickly sectioned melanoma tissues with scanning acoustic microscopy

NASA Astrophysics Data System (ADS)

Miyasaka, C.; Tittmann, B. R.; Tutwiler, R.; Tian, Y.; Maeva, E.; Shum, D.

2010-03-01

The present study is to investigate the feasibility of applying in-vivo acoustic microscopy to the analysis of cancerous tissue. The study was implemented with mechanical scanning reflection acoustic microscope (SAM) by the following procedures. First, we ultrasonically visualized thick sections of normal and tumor tissues to determine the lowest transducer frequency required for cellular imaging. We used skin for normal tissue and the tumor was a malignant melanoma. Thin sections of the tissue were also studied with the optical and high-frequency-ultrasonic imaging for pathological evaluation. Secondly, we ultrasonically visualized subsurface cellular details of thin tissue specimens with different modes (i.e., pulse and tone-burst wave modes) to obtain the highest quality ultrasonic images. The objective is to select the best mode for the future design of a future SAM for in-vivo examination. Thirdly, we developed a mathematical modeling technique based on an angular spectrum approach for improving image processing and comparing numerical to experimental results.

Comparative Petrographic Maturity of River and Beach Sand, and Origin of Quartz Arenites.

ERIC Educational Resources Information Center

Ferree, Rob A.; And Others

1988-01-01

Describes a deterministic computer model that incorporates: (1) initial framework composition; (2) abrasion factors for quartz, feldspar, and rock fragments; and (3) a fragmentation ratio for rock fragments to simulate the recycling of coastal sands by rivers and beaches. (TW)

The Luizi Structure (Democratic Republic of Congo) — First Confirmed Meteorite Impact Crater in Central Africa

NASA Astrophysics Data System (ADS)

Ferrière, L.; Lubala, F. R. T.; Osinski, G. R.; Kaseti, P. K.

2011-03-01

Our detailed analysis of the Luizi structure, combining a remote sensing study with geological field observations and petrographic examination of rock samples collected during our 2010 field campaign allows us to confirm its meteorite impact origin.

Nature of migrabitumen and their relation to regional thermal maturity, Ouachita Mountains, Oklahoma

USGS Publications Warehouse

Cardott, Brian J.; Ruble, Tim E.; Suneson, Neil H.

1993-01-01

Two grahamite and three impsonite localities are within an 82-km-long segment of the Ouachita Mountains of southeastern Oklahoma. Grab samples were collected to study the petrographic and geochemical characteristics of the migrabitumen at the grahamite-impsonite transition and the relation of the migrabitumen to the regional thermal maturity pattern. Maximum and random bitumen reflectance values increased from 0.75 to 1.80% from west to east, consistent with the regional thermal maturation trend. Mean bireflectance values increased from 0.04 to 0.38%. The two grahamite samples are classified at the grahamite-impsonite boundary with conflicting petrographic (bitumen reflectance) and bulk chemical (volatile matter) maturity indicators. The regional maturation trend, based on vitrinite reflectance and bitumen reflectance values, was confirmed by a detailed geochemical investigation of bitumen extracts. Although biomarker analyses were influenced by extensive biodegradation effects, molecular parameters based on the phenanthrenes, dibenzothiophenes, and tricyclic terpanes were identified as useful maturity indicators.

A Test of the Biogenicity Criteria Established for Microfossils and Stromatolites on Quaternary Tufa and Speleothem Materials Formed in the "Twilight Zone" at Caerwys, UK.

PubMed

Brasier, A T; Rogerson, M R; Mercedes-Martin, R; Vonhof, H B; Reijmer, J J G

2015-10-01

The ability to distinguish the features of a chemical sedimentary rock that can only be attributed to biology is a challenge relevant to both geobiology and astrobiology. This study aimed to test criteria for recognizing petrographically the biogenicity of microbially influenced fabrics and fossil microbes in complex Quaternary stalactitic carbonate rocks from Caerwys, UK. We found that the presence of carbonaceous microfossils, fabrics produced by the calcification of microbial filaments, and the asymmetrical development of tufa fabrics due to the more rapid growth of microbially influenced laminations could be recognized as biogenic features. Petrographic evidence also indicates that the development of "speleothem-like" laminae was related to episodes of growth interrupted by intervals of nondeposition and erosion. The lack of any biogenic characteristics in these laminae is consistent with their development as a result of variation in the physicochemical parameters that drive calcite precipitation from meteoric waters in such environmental settings.

Mercury content and petrographic composition in Pennsylvanian coal beds of Indiana, USA

USGS Publications Warehouse

Mastalerz, Maria; Drobniak, A.; Filippelli, G.

2006-01-01

A suite of high volatile bituminous coals of Pennsylvanian age from Indiana has been studied for their mercury (Hg) concentration and relationship between mercury content and maceral and lithotype composition. The coals ranged in Hg content from 0.02 in the Danville Coal Member to 0.31 ppm in the Upper Block Coal Member. Our study indicates that relationships between petrographic composition of coal and mercury content are site specific. This lack of a consistent relationship is explained by the fact that most Hg occurs in pyrite and not in the organic matter itself. Comparison of Hg content in durain/vitrain pairs shows that durain has more frequently a higher Hg content than vitrain, but the difference in frequency is inconsequential and shows no consistent pattern for a single coal bed or a single location. We suggest that increased concentration of Hg in vitrain is related to the presence of epigenetic pyrite in cleats. ?? 2006 Elsevier B.V. All rights reserved.

Petrographic and geochemical characteristic of volcanic rocks from Tasik Kenyir and Kampung Awah, East Malaya block, Peninsular Malaysia

NASA Astrophysics Data System (ADS)

Roselee, Muhammad Hatta; Umor, Mohd Rozi; Ghani, Azman Abdul; Badruldin, Muhamad Hafifi; Quek, Long Xiang

2018-04-01

Kampung Awah and Tasik Kenyir are geologically located in East Malaya Blocks. These block is also known as western margin of Indochina terrane. Apart from sedimentary formations, East Malaya Blocks is also dominated by plutonic and volcanic rocks of mafic to rhyolitic compositions. Petrography and geochemical data suggest that Kampung Awah and Tasik Kenyir are one of locations which consists of volcanic rocks of generally basaltic to basaltic andesite compositions. Volcanic rocks from both area consists of plagioclcase, clinopyroxene, orthpyroxene as main mineral constituents with minor occurrences of hornblende. Geochemical data also indicate that volcanic rocks from both area were formed during subduction of the Paleo-tethys oceanic underneath the East Malaya Block or Indochina terrane. Most of the samples are metaluminous which indicate the volcanics are derived from igneous origin. This paper will contribute new geochemical data of mafic volcanics from Kampung Awah and Tasik Kenyir with the support of petrographic and field evidence to deduce the magma evolution and the tectonic setting.

Close or not so close? Provenance studies of megalithic monuments from Alentejo (Portugal)

NASA Astrophysics Data System (ADS)

Boaventura, R.; Moita, P.

2012-04-01

There has been a significant amount of studies about megalithic tombs conducted in the Alentejo region. However the geological provenance of monoliths used in the construction of those tombs usually was not a priority among researchers with rare exceptions (Dehn, Kalb and Vortisch, 1991; Boaventura, 2000). Recent studies of dolmens (Oliveira, 1997 and 2006; Gonçalves, 2003) refer only to a brief characterization of rocks, such as "granite or schist slabs", highlighting certain types if the geological stratum is identical or not to the stone blocks. On the other hand, when the type of raw material appears to be similar with the bedrock, it is common and empirically assumed its local provenance. With the aim of testing and expand the knowledge about the provenance of the slabs used in the construction of megalithic tombs, several lithic samples from dolmen slabs and outcrops in their surroundings were collected for analysis and comparison. The samples were characterized by petrographic studies in thin section as well with a geochemical analyses performed by XRF that gives major elements as well some trace elements. The dolmens tested for this project are located roughly between the northeast to west of the town of Monforte (Upper region of Alentejo, Portugal) and are named, from south to north, as Serrinha, Rabuje group (1 to 5), Geodésico de Besteiros 3 and Velho. The field work and petrographic studies revealed that the slabs are constituted mainly by several types of granitoids (gnaissic, red, white, tonalitic), amphibolites and mottled schist shale. The comparison of chemical analyses between slabs and selected outcrops revealed that the provenances are in most of the cases from the nearby geological stratum. In fact, major elements (e.g. MgO, SiO2, CaO) as well trace elements (e.g. Sr, Y, Zr, Nb) compositions are similar on slab samples and in rocks from the outcrops. If in terms of major elements a similarity was already expectable, or easier to obtain, the trace elements (namely immobile elements such as Y or Nb) compositions corroborated that slabs and geological bedrock were alike. The capstone slab that covers the dolmen of Rabuje 1 group does not belong to the nearby geological stratum. Nevertheless, a probable matching source-outcrop was located sampled and characterized in terms of geochemistry and petrograpphy and compared with the megalithic capstone. This work allowed a better characterization of the rocks used in megalithic tombs as well as corroborat a pragmatic attitude of Neolithic populations in the search of the appropriate slabs for construction as proposed previously (Boaventura, 2000). When available, the megalithic stones were likely collected from the nearby stratum and therefore the distances traveled were small (in situ or less than 1-2 km). Nevertheless, when the type of stone needed was not available in the vicinity (e.g fracturing provided only smaller stones) it would be necessary to travel longer distances, up to 8 km (Boaventura, 2000), as in the case of the dolmen of Rabuje 1. Boaventura, R. (2000) - A geologia das Antas de Rabuje (Monforte, Alentejo), Revista Portuguesa de Arquelogia.Vol. 3;2.pp-15-23. Dehn, W. Kalb, P. and Vortich, W. (1991) - Geologisch-Petrographische Untersuchungen an Megalithgräbern Portugals. Madrider Mitteilungen, 32, p. 1-28. Oliveira, J. (1997) - Monumentos megalíticos da bacia hidrográfica do Rio Sever. Ibn Maruan. Castelo de Vide. Special Edition. Oliveira, J. (2006) - Património arqueológico da Coudelaria de Alter e as primeiras comunidades agropastoris. [Évora]: Colibri.

Paleocene Turbidite Deposition in the Central American Seaway (NW Costa Rica): Geochemical Analysis and Provenance of Detrital Spinel and Clinopyroxene

NASA Astrophysics Data System (ADS)

Giblin, A. C.

2015-12-01

The Central American Land Bridge is the crucial connection between North and South America, and the Miocene closure of the Panama seaway led to a change in global oceanic circulation patterns. Modern Costa Rica is part of the island arc that formed over the western Caribbean subduction zone, and the Santa Elena peninsula is on the northwest coast of Costa Rica next to the Sandino forearc basin. This study focuses on the origin and provenance of the Paleocene deep-water Rivas and Descartes turbidites that crop out on the northern part of the Santa Elena peninsula in northwestern Costa Rica. Understanding the sedimentary fill of the Sandino Basin that contributed to the closing of the seaway may lead to a better understanding of the Late Cretaceous-Paleogene arcs. Provenance studies of the Santa Elena Peninsula turbidite sandstone bodies constrain the history of the paleogeography and tectonics of the region. Petrographic analyses of rock thin sections constrain source areas; geochemical analysis of individual detrital heavy minerals from rock samples give indications of sediment sources and tectonic setting during deposition. This study is a provenance analysis based on (i) semi-quantitative energy-dispersive spectrometry analysis of heavy minerals, (ii) quantitative wavelength-dispersive spectrometry for major elements of detrital clinopyroxene and spinel grains, (iii) trace element analysis through laser ablation of single detrital clinopyroxene grains, and (iv) comparative analysis of the different potential source rocks to clearly identify the most likely sediment sources. The detrital spinel and clinopyroxene are possibly sourced from: mantle ophiolites, mid-ocean ridge gabbros, or volcanic arc tholeiitic basalts or calc-alkaline andesites. Spinel and clinopyroxne geochemistry suggests a possible peridotitic source, linked to mantle rocks that are now covered by Tertiary volcanics or have completely eroded. The character of the crustal minerals indicates sources from mid-ocean ridge gabbros, and island arc tholeiites and andesites. This suggests that during the early history of the gateway uplift and seaway closure, sediment sources were dominated first by older ophiolites and gabbroic sources, then by volcanic inputs from the arc.

REE Distribution in Cultivated and No Cultivated Soils in Two Viticultural Areas of Central Chile: Mineralogical, Pedological and Anthropic Influences

NASA Astrophysics Data System (ADS)

Castillo, P.; Townley, B.; Aburto, F.

2017-12-01

Within the scope of a Corfo-Innova Project (I+D Wines of Chile-University of Chile) we have recognized remarkable REE patterns in soils of two vineyards located in traditional vinicultural areas: Casablanca and Santa Cruz. Both vineyards have granitic parent rock, with similar petrographic features and REE patterns. We studied REE distribution on twelve cultivated soil profiles at each vineyard, where a full mineralogical, geochemical and pedogenic sampling and characterization was performed. To establish the effect of management no cultivated soil profiles were included from each vineyard location. REE in soil samples were measured by ICP-MS using two digestion methods: lithium metaborate/tetraborate fusion to obtain REE contents in total soil and MMI® partial extraction technique for REE contents on bioavailable phases.Soils display similar signatures of REEs respect to the rock source at both vineyards, but showing relative enrichments in soils of Casablanca and depletion in soils of Santa Cruz. Bioavailable phase data indicates a relative depletion of LREEs compared to HREEs and different anomalies for Ce (positive vs negative) in different areas of the same vineyard. Similar patterns of soils and parent rock suggest that REEs are adequate tracers of lithological source. Enrichments and/or depletions of REE patterns in soils respect to the rock source and Ce anomalies, evidence differential pedogenetic processes occurring at each sampled site. Results of bioavailable phase are coherent with the immobilization and fractionation of LREEs by stable minerals within soils as clays and Fe oxides. Mineralogical results in soil thin sections of Casablanca evidence the occurrence of Ti phases as sphene, ilmenite and rutile, which probably control the relative REE enrichment, since these minerals are considered more stable under pedogenic conditions.Finally, cultivated soils show a depleted but analogous pattern of REE regarding to no cultivated soil, indicating the REEs loss due to agricultural land use. Our preliminary hypothesis is the existence of organometallic complexes that retain REEs in natural soils, which are degraded with vinicultural management. However other factors as differential weathering rates of minerals, clays mineralogy and fractionation of REE by plants must be considered.

Preservation and detection of microstructural and taxonomic correlations in the carbon isotopic compositions of individual Precambrian microfossils

NASA Astrophysics Data System (ADS)

Williford, Kenneth H.; Ushikubo, Takayuki; Schopf, J. William; Lepot, Kevin; Kitajima, Kouki; Valley, John W.

2013-03-01

Here we present techniques for, and new data from, in situ carbon isotope (δ13C) analysis of Precambrian permineralized microscopic fossils with a reproducibility of 1-2‰ using secondary ion mass spectrometry (SIMS). Individual microfossils, selected for their excellent preservation, were analyzed in petrographic thin sections of stromatolitic cherts from the Proterozoic Gunflint (˜1880 Ma), Bitter Springs (˜830 Ma), Min'yar (˜740 Ma), and Chichkan (˜775 Ma) Formations. The range of δ13C values (-34.6‰ to -22.1‰ VPDB) among the 46 individuals analyzed falls within that expected for photoautotrophic carbon fixation by ribulose bisphosphate carboxylase (RuBisCO), consistent with morphology-based taxonomic assignments for these specimens. Microfossils classified as cyanobacteria from the Gunflint, Bitter Springs, and Min'yar Formations (for which published carbonate carbon isotope data can be used to estimate the δ13C of the original dissolved inorganic carbon substrate) exhibit a consistent ˜19‰ total fractionation (δ13C of dissolved inorganic carbon - δ13C of biomass) similar to that observed in living cyanobacteria, over a wide range of δ13Ccarb values (-2.9‰ to 3.4‰). In stromatolitic chert of the Min'yar Formation, morphologically diverse microfossils preserved in a ˜1 mm2 part of a microbial mat exhibit systematic isotopic differences among and within taxa that correlate with their morphologically inferred biological affinities and suggest that isotopic signatures of their original biosynthetic processes (e.g., lipid and peptidoglycan synthesis) are preserved. Isotopic offsets consistent with the different RuBisCO-based fractionations typical of cyanobacteria and photosynthetic eukaryotes are documented by the differing δ13C values of a colonial cyanobacterium (-22.6 ± 0.5‰) and a phytoplanktonic protistan acritarch (-28.9 ± 1.0‰) situated <1 cm apart in the stromatolitic Chichkan chert. These findings show for the first time the possibility of using in situ isotopic microanalysis of fossil microbial mats and ancient sediments in order to distinguish metabolic fingerprints within complex microbial ecosystems and consortia.

Geomechanical Modeling of Deformation Banding in the Navajo Sandstone, San Rafael Monocline, Utah

NASA Astrophysics Data System (ADS)

Gutierrez, M.; Sundal, A.; Petrie, E. S.

2017-12-01

Deformation bands are ubiquitous geological features in many types of rocks. Depending on their micro-structure, they can act either as conduits or barriers to fluid flow. Given the significant roles deformation bands play in fluid flow and chemical transport in rocks, it is important to develop fundamental understanding of their origin, and their characteristics as they relate with the host rock properties and their depositional and structural-geological history. We present a forward-modeling technique based on the geomechanical Bifurcation Theory (BT) to predict the formation of deformation bands in sandstone. According to BT, the formation of deformation bands is a result of strain location, which in turn stems from instability in the stress-strain response of materials during loading. Due to bifurcation, a material which undergoes homogeneous deformation can reach a point at which the material experiences instability and deformation starts to become non-homogenous. We implemented BT in the commercially-available geomechanical code FLAC (Fast Langragian Analysis of Continua) and applied it in the field-scale modeling of deformation banding in the Navajo Sandstone in the San Rafael Monocline in Utah induced by fault propagation folding. The results show that geomechanical modeling using BT has a powerful potential to simulate the physical processes in the formation of deformation banding in rocks. Predicted deformation bands, specifically the pervasive bedding-parallel bands in the Navajo sandstone formation, normal faulting in the upper limb and reverse faulting in the lower limb, are generally in agreement with field observations. Predictions indicate that the pervasive bedding-parallel bands in the Navajo Sandstone are transitional compaction-shear bands with alternating zones of volumetric compaction and dilation. These predictions are consistent with petrographic analysis of thin sections of rock samples from the Navajo Sandstone. The most important parameter in the geomechanical modeling is the dilation angle in relation to the friction angle of the host rock. These parameters, as well the elastic properties, should evolve during the geologic history of a site, thus, the main challenge in the modeling is how to calibrate these parameters to yield consistent results.

Micro-X-ray diffraction assessment of shock stage in enstatite chondrites

NASA Astrophysics Data System (ADS)

Izawa, Matthew R. M.; Flemming, Roberta L.; Banerjee, Neil R.; McCausland, Philip J. A.

2011-05-01

A new method for assessing the shock stage of enstatite chondrites has been developed, using in situ micro-X-ray diffraction (μXRD) to measure the full width at half maximum (FWHMχ) of peak intensity distributed along the direction of the Debye rings, or chi angle (χ), corresponding to individual lattice reflections in two-dimensional XRD patterns. This μXRD technique differs from previous XRD shock characterization methods: it does not require single crystals or powders. In situ μXRD has been applied to polished thin sections and whole-rock meteorite samples. Three frequently observed orthoenstatite reflections were measured: (020), (610), and (131); these were selected as they did not overlap with diffraction lines from other phases. Enstatite chondrites are commonly fine grained, stained or darkened by weathering, shock-induced oxidation, and metal/sulfide inclusions; furthermore, most E chondrites have little olivine or plagioclase. These characteristics inhibit transmitted-light petrography, nevertheless, shock stages have been assigned MacAlpine Hills (MAC) 02837 (EL3) S3, Pecora Escarpment (PCA) 91020 (EL3) S5, MAC 02747 (EL4) S4, Thiel Mountains (TIL) 91714 (EL5) S2, Allan Hills (ALHA) 81021 (EL6) S2, Elephant Moraine (EET) 87746 (EH3) S3, Meteorite Hills (MET) 00783 (EH4) S4, EET 96135 (EH4-5) S2, Lewis Cliff (LEW) 88180 (EH5) S2, Queen Alexandra Range (QUE) 94204 (EH7) S2, LaPaz Icefield (LAP) 02225 (EH impact melt) S1; for the six with published shock stages, there is agreement with the published classification. FWHMχ plotted against petrographic shock stage demonstrates positive linear correlation. FWHMχ ranges corresponding to shock stages were assigned as follows: S1 < 0.7°, S2 = 0.7-1.2°, S3 = 1.2-2.3°, S4 = 2.3-3.5°, S5 > 3.5°, S6—not measured. Slabs of Abee (EH impact-melt breccia), and Northwest Africa (NWA) 2212 (EL6) were examined using μXRD alone; FWHMχ values place both in the S2 range, consistent with literature values. Micro-XRD analysis may be applicable to other shocked orthopyroxene-bearing rocks.

Mineral Precipitation in Fractures: Multiscale Imaging and Geochemical Modeling

NASA Astrophysics Data System (ADS)

Hajirezaie, S.; Peters, C. A.; Swift, A.; Sheets, J. M.; Cole, D. R.; Crandall, D.; Cheshire, M.; Stack, A. G.; Anovitz, L. M.

2017-12-01

For subsurface energy technologies such as geologic carbon sequestration, fractures are potential pathways for fluid migration from target formations. Highly permeable fractures may become sealed by mineral precipitation. In this study, we examined shale specimens with existing cemented fractures as natural analogues, using an array of imaging methods to characterize mineralogy and porosity at several spatial scales. In addition, we used reactive transport modeling to investigate geochemical conditions that can lead to extensive mineral precipitation and to simulate the impacts on fracture hydraulic properties. The naturally-cemented fractured rock specimens were from the Upper Wolfcamp formation in Texas, at 10,000 ft depth. The specimens were scanned using x-ray computed tomography (xCT) at resolution of 13 microns. The xCT images revealed an original fracture aperture of 1.9 mm filled with several distinct mineral phases and vuggy void regions, and the mineral phase volumes and surface areas were quantified and mapped in 3D. Specimens were thin-sectioned and examined at micron- and submicron-scales using petrographic microscopy (PM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and small angle X-ray scattering (SAXS). Collectively these methods revealed crystals of dolomite as large as 900 microns in length overlain with a heterogeneous mixture of carbonate minerals including calcite, dolomite, and Fe-rich dolomite, interspersed at spatial scales as small as 5 microns. In addition, secondary precipitation of SiO2 was found to fill some of the void space. This multiscale imaging was used to inform the reactive transport modeling employed to examine the conditions that can cause the observed mineral precipitation in fractures at a larger scale. Two brines containing solutions that when mixed would lead to precipitation of various carbonate minerals were simulated as injectants into a fracture domain. In particular, the competing effects of transport dynamics and reaction kinetics were investigated in the context of profiles of the precipitated minerals and permeability behavior of the fracture flow path. This study contributes rich knowledge toward mastering the subsurface for energy production and storage and for the management of energy waste streams.

Characterization of fieldstone for a provenance study of local building stones and artifacts

NASA Astrophysics Data System (ADS)

Goossens, M.; De Kock, T.; Dewanckele, J.; Boone, M.; De Boever, W.; Brabant, L.; Louwye, S.; De Ceukelaire, M.; Vanhaecke, F.; Cnudde, V.

2012-04-01

Fieldstone is a Belgian silicified sandstone speckled with glauconite. The hardness varies with the degree of silicification and its colour, which is usually greenish, can differ from bluish gray to orange depending on the degree of oxidation of the glauconite. Although recently discovered in the clayey interlayers, fieldstone mainly appears in the sandy units of the Eocene in Western Flanders (Belgium). It occurs as lenses and banks parallel to the stratification. From Roman times onwards, these were locally intensely cultivated as local building stones. Furthermore archeological evidence points out fieldstone was used in prehistoric times to make various artifacts like scrapers and jacks. The purpose of our study is to characterize fieldstone from the different known geographical and stratigraphical localities. Ambiguous stratigraphical classifications of fieldstone outcrops in the past have complicated previous studies of fieldstone. Therefore, we aim to provide clarity over its stratigraphical occurrence and deliver additional information about its formation. The ultimate goal is to trace back the origin of the fieldstone used in buildings and for archeological artifacts to a distinct locality. For the characterization of the fieldstone different techniques were used. Thin sections were examined by petrographical microscopy in order to study grain size, porosity, mineralogy, degree of silicification and in some samples microfossil content like silicified foraminifers. Porosity was determined with volumetric analysis and high resolution X-ray computer tomography. Attention towards the dinoflagellate content was given. This can provide information about the age and depositional environment of the silicified sands. In addition, it can act as a distinct feature that is characteristic for one locality or stratigraphic layer. A selected amount of samples were chemically analysed with Laser Ablation Inductively Coupled Plasma Mass Spectrometer in order to check if this could provide a chemical fingerprint which can be used to distinguish fieldstone coming from different localities from each other. By combining all this information we aim at composing an outline to trace back the origin of the fieldstone used as building stone and for artifacts.

Forensic Geopedology and Micropedology: New Indications and Lookouts from Pigs Experimental Burials.

NASA Astrophysics Data System (ADS)

Ern, Stephania Irmgard Elena; Trombino, Luca

2013-04-01

The role played by soil scientists in the modern forensic science is very real and important, above all in the crime scenes when buried remains, both strongly decomposed or skeletal, are found. Thanks to a PhD project on Forensic Geopedology, an interdisciplinary team of the Universities of Milano and Milano Bicocca, has been working for the last four years on several sets of experimental burials of pigs and piglets, in different soil types and for different times of burial, in order to get new evidences on environmental responses to the burial, including geopedological and micropedological aspects. The present work constitutes a conclusive synthesis of results emerged from comparative soil characterizations, listed as follow: - Grainsize analyses; - Determination of pH in H2O and KCl; - Total Nitrogen and Organic Carbon analyses: - Quantification of Available Phosphorous; - Determination of Cation Exchange Capacity and Base Saturation; - Analyses of Volatile Fatty Acids; - Scanning Electron Microscope and Energy Dispersive Spectroscopy analyses; - Petrographic Optical Microscope analyses (including thin sections descriptions). It is proposed a diachronic picture of the project where it is possible to follow the variability of significance of the different kinds of analyses carried out. The achieved results, especially when cross-checked, are very stimulating as regards the setting of analytical protocols for: - The determination of time since burial (TSB); - The discrimination between primary and secondary burials; - The identification of corpses concealments. All the analyses and different approaches discussed and addressed in this work require extreme care when applied to real forensic scenarios; however, the protocols tested can be a piece of a large and articulated puzzle that depicts the major forensic case studies in which Geopedology can be of help in solving problems or in answering some peculiar questions. It is important to understand that a science so rich in variability, as soil science is, has a great potential to reconstruct and solve various forensic cases. Many studies and experiments still need to be carried out to improve the knowledge of the specific processes, in order to give the correct answer to forensic and legal questions, together with the aim of reaching standardization for the analyses carried out.

Effect of damage on elastically tailored composite laminates

NASA Technical Reports Server (NTRS)

Armanios, Erian; Badir, Ashraf; Berdichevsky, Victor

1991-01-01

A variationally consistent theory is derived in order to predict the response of anisotropic thin-walled closed sections subjected to axial load, torsion and bending. The theory is valid for arbitrary cross-sections made of laminated composite materials with variable thickness and stiffness. Closed form expressions for the stiffness coefficients are provided as integrals in terms of lay-ups parameters and cross-sectional geometry. A comparison of stiffness coefficients and response with finite element predictions and a closed form solution is performed. The theory is applied to the investigation of the effect of damage on the extension-twist coupling in a thin-walled closed section beam. The damage is simulated as a progressive ply-by-ply failure. Results show that damage can have a significant effect on the extension-twist coupling.

Cross Section High Resolution Imaging of Polymer-Based Materials

NASA Astrophysics Data System (ADS)

Delaportas, D.; Aden, P.; Muckle, C.; Yeates, S.; Treutlein, R.; Haq, S.; Alexandrou, I.

This paper describes a methodology for preparing cross sections of organic layers suitable for transmission electron microscopy (TEM) at high resolution. Our principal aim is to prepare samples that are tough enough to allow the slicing into sub-150 nm sections. We also need strong contrast at the organic layer area to make it identifiable during TEM. Our approach is to deposit organic layers on flexible substrates and prepare thin cross sections using ultra-microtomy. We sandwich the organic layer between two metal thin films in order to isolate it and improve contrast. Our methodology is used to study the microstructure of polymer/nanotube composites, allowing us to accurately measure the organic layer thickness, determine nanotube dispersion and assess the effect of nanotube clustering on film structural stability.

Combination Of Investment And Centrifugal Casting

NASA Technical Reports Server (NTRS)

Creeger, Gordon A.

1994-01-01

Modifications, including incorporation of centrifugal casting, made in investment-casting process reducing scrap rate. Used to make first- and second-stage high-pressure-fuel-turbopump nozzles, containing vanes with thin trailing edges and other thin sections. Investment mold spun for short time while being filled, and stopped before solidification occurs. Centrifugal force drives molten metal into thin trailing edges, ensuring they are filled. With improved filling, preheat and pour temperatures reduced and solidification hastened so less hot tearing.

Stratigraphy, structure, and some petrographic features of Tertiary volcanic rocks in the USW G-2 drill hole, Yucca Mountain, Nye County, Nevada

USGS Publications Warehouse

Maldonado, Florian; Koether, S.L.

1983-01-01

A continuously cored drill hole designated as USW G-2, located at Yucca Mountain in southwestern Nevada, penetrated 1830.6 m of Tertiary volcanic strata composed of abundant silicic ash-flow tuffs, minor lava and flow breccias, and subordinate volcaniclastic rocks. The volcanic strata penetrated are comprised of the following in descending order: Paintbrush Tuff (Tiva Canyon Member, Yucca Mountain Member, bedded tuff, Pah Canyon Member, and Topopah Spring Member), tuffaceous beds of Calico Hills, Crater Flat Tuff (Prow Pass Member, Bullfrog Member, and Tram unit), lava and flow breccia (rhyodacitic), tuff of Lithic Ridge, bedded and ash-flow tuff, lava and flow breccia (rhyolitic, quartz latitic, and dacitic), bedded tuff, conglomerate and ash-flow tuff, and older tuffs of USW G-2. Comparison of unit thicknesses at USW G-2 to unit thicknesses at previously drilled holes at Yucca Mountain indicate the following: (1) thickening of the Paintbrush Tuff members and tuffaceous beds of Calico Hills toward the northern part of Yucca Mountain; (2) thickening of the Prow Pass Member but thinning of the Bullfrog Member and Tram unit; (3) thinning of the tuff of Lithic Ridge; (4) presence of approximately 280 m of lava and flow breccia not previously penetrated by any drill hole; and (5) presence of an ash-flow tuff unit at the bottom of the drill hole not previously intersected, apparently the oldest unit penetrated at Yucca Mountain to date. Petrographic features of some of the units include: (1) decrease in quartz and K-feldspar and increases in biotite and plagioclase with depth in the tuffaceous beds of Calico Hills; (2) an increase in quartz phenocrysts from the top to the bottom members of the Crater Flat Tuff; (3) a low quartz content in the tuff of Lithic Ridge, suggesting tapping of the magma chamber at quartz-poor levels; (4) a change in zeolitic alteration from heulandite to clinoptilolite to mordenite with increasing depth; (5) lavas characterized by a rhyolitic top and dacitic base, suggesting reverse compositional zoning; and (6) presence of hydrothermal mineralization in the lavas that could be related to an intrusive under Yucca Mountain or to volcanism associated with the Timber Mountain-Claim Canyon caldera complex. A fracture analysis of the core resulted n tabulation of 7,848 fractures, predominately open and high angle. The fractures were filled or coated with material in various combinations and include the following in decreasing abundance: CaCo3, iron oxides and hydroxides, SiO2, manganese oxides and hydroxides, clays and zeolites. An increase in the intensity of fracturing can be correlated with the following: (1) densely welded zones, (2) lithophysal zones, (3) vitrophyre, (4) silicified zones, (5) fault zones, and (6) cooling joints. Numerous fault zones were penetrated by the drill hole, predominately in the lithophysal zone of the Topopah Spring Member and below the tuffaceous beds of Calico Hills. The faults are predominately high angle with both a vertical and lateral component. Three major faults were penetrated, two of which intersect the ground surface, with displacements of at least 20 m and possibly as much as 52 m. The faults and some fractures are probably related to the regional doming of the area associated with the volcanism-tectonism of the Timber Mountain-Claim Canyon caldera complex, and to Basin and Range tectonism.

An evaluation of the performance of concretes containing fly ash and ground slag in bridge decks.

DOT National Transportation Integrated Search

2006-01-01

Cores from 36 bridge decks were evaluated to assess the condition and quality of the concrete by petrographic methods and direct and indirect measures of the transport properties. Transport properties were measured by a rate of absorption test (ASTM ...

Integrated ultrasonic and petrographical characterization of carbonate building materials

NASA Astrophysics Data System (ADS)

Ligas, Paola; Fais, Silvana; Cuccuru, Francesco

2014-05-01

This paper presents the application of non-destructive ultrasonic techniques in evaluating the conservation state and quality of monumental carbonate building materials. Ultrasonic methods are very effective in detecting the elastic characteristics of the materials and thus their mechanical behaviour. They are non-destructive and effective both for site and laboratory tests, though it should be pointed out that ultrasonic data interpretation is extremely complex, since elastic wave velocity heavily depends on moisture, heterogeneity, porosity and other physical properties of the materials. In our study, considering both the nature of the building materials and the constructive types of the investigated monuments, the ultrasonic investigation was carried out in low frequency ultrasonic range (24 kHz - 54 kHz) with the aim of detecting damages and degradation zones and assessing the alterability of the investigated stones by studying the propagation of the longitudinal ultrasonic pulses. In fact alterations in the materials generally cause a decrease in longitudinal pulse velocity values. Therefore starting from longitudinal velocity values the elasto-mechanical behaviour of the stone materials can be deduced. To this aim empirical and effective relations between longitudinal velocity and mechanical properties of the rocks can be used, by transferring the fundamental concepts of the studies of reservoir rocks in the framework of hydrocarbon research to the diagnostic process on stone materials. The ultrasonic measurements were performed both in laboratory and in situ using the Portable Ultrasonic Non-Destructive Digital Indicating Tester (PUNDIT) by C.N.S. Electronics LTD. A number of experimental sessions were carried out choosing different modalities of data acquisition. On the basis of the results of the laboratory measurements, an in situ ultrasonic survey on significant monuments, have been carried out. The ultrasonic measurements were integrated by a petrographical and petrophysical study of the investigated stone materials to correlate their petrographical-petrophysical features with the elastic ones. From this integrated study results that the modifications in the elasto-mechanical and petrographical-petrophysical features of the investigated carbonate materials are the main causes which reduce their quality as building materials. The use of the ultrasonic method integrated with information on petrography and petrophysics of the rocks has been successful to assess the rock quality and better understanding their alteration process. Acknowledgments: This work was financially supported by Sardinian Local Administration (RAS - LR 7 August 2007, n.7, Promotion of Scientific Research and Innovation in Sardinia - Italy, Responsible Scientist: S. Fais).

21 CFR 862.2270 - Thin-layer chromatography system for clinical use.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Thin-layer chromatography system for clinical use. 862.2270 Section 862.2270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory...

21 CFR 862.2270 - Thin-layer chromatography system for clinical use.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Thin-layer chromatography system for clinical use. 862.2270 Section 862.2270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory...

21 CFR 862.2270 - Thin-layer chromatography system for clinical use.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Thin-layer chromatography system for clinical use. 862.2270 Section 862.2270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory...

21 CFR 177.2550 - Reverse osmosis membranes.

Code of Federal Regulations, 2014 CFR

2014-04-01

... maximum weight is 62 milligrams per square decimeter (4 milligrams per square inch) as a thin film... square decimeter (0.3 milligrams per square inch) as a thin film composite on a suitable support. The... square decimeter (0.03 milligrams per square inch). (3) For the purpose of this section, the reverse...

Peripheral Precocious Puberty Caused by Human Chorionic Gonadotropin Producing Pineal Gland Tumor.

PubMed

Hammadur Rahaman, S K; Khandelwal, Deepak; Khadgawat, Rajesh; Kandasamy, Devasenathipathy; Bakhshi, Sameer

2018-03-15

Pineal gland lesions usually present with central precocious puberty. A 3½-yr-old boy presented with precocious puberty. Clinically and biochemically, it was gonadotropin releasing hormone (GnRH) independent. Serum and CSF beta-hCG levels were increased. Thin section magnetic resonance imaging of brain revealed a pineal gland tumor. He received chemotherapy followed by radiotherapy and responded well. CSF beta-hCG should be measured in all cases of peripheral precocity, and if CSF beta-hCG is elevated, thin section magnetic resonance imaging of brain should be considered.

Evaluation of Reaction Cross Section Data Used for Thin Layer Activation Technique

NASA Astrophysics Data System (ADS)

Ditrói, F.; Takács, S.; Tárkányi, F.

2005-05-01

Thin layer activation (TLA) is a widely used nuclear method to investigate and control the loss of material during wear, corrosion and erosion processes. The process requires knowledge of depth profiles of the investigated radioisotopes produced by charged particle bombardment. The depth distribution of the activity can be determined with direct, very time-consuming step by step measurement or by calculation from reliable cross section, stopping power and sample composition data. These data were checked experimentally at several points performing only a couple of measurements.

Evaluation of Reaction Cross Section Data Used for Thin Layer Activation Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ditroi, F.; Takacs, S.; Tarkanyi, F.

2005-05-24

Thin layer activation (TLA) is a widely used nuclear method to investigate and control the loss of material during wear, corrosion and erosion processes. The process requires knowledge of depth profiles of the investigated radioisotopes produced by charged particle bombardment. The depth distribution of the activity can be determined with direct, very time-consuming step by step measurement or by calculation from reliable cross section, stopping power and sample composition data. These data were checked experimentally at several points performing only a couple of measurements.

Local Deplanation Of Double Reinforced Beam Cross Section Under Bending

NASA Astrophysics Data System (ADS)

Baltov, Anguel; Yanakieva, Ana

2015-12-01

Bending of beams, double reinforced by means of thin composite layers, is considered in the study. Approximate numerical solution is proposed, considering transitional boundary areas, where smooth quadratic transition of the elasticity modulus and deformations take place. Deplanation of the cross section is also accounted for in the areas. Their thickness is found equalizing the total stiffness of the cross section and the layer stiffness. Deplanation of the cross section of the transitional area is determined via the longitudinal deformation in the reinforcing layer, accounting for the equilibrium between the internal and the external moment, generated by the longitudinal stresses in the cross section. A numerical example is given as an illustration demonstrating model's plausibility. The model allows the design and the calculation of recycled concrete beams double reinforced by means of thin layers. The approach is in agreement with modern design of nearly zero energy buildings (NZEB).

The potential hydrothermal systems unexplored in the Southwest Indian Ocean

NASA Astrophysics Data System (ADS)

Suo, Yanhui; Li, Sanzhong; Li, Xiyao; Zhang, Zhen; Ding, Dong

2017-06-01

Deep-sea hydrothermal vents possess complex ecosystems and abundant metallic mineral deposits valuable to human being. On-axial vents along tectonic plate boundaries have achieved prominent results and obtained huge resources, while nearly 90% of the global mid-ocean ridge and the majority of the off-axial vents buried by thick oceanic sediments within plates remain as relatively undiscovered domains. Based on previous detailed investigations, hydrothermal vents have been mapped along five sections along the Southwest Indian Ridge (SWIR) with different bathymetry, spreading rates, and gravity features, two at the western end (10°-16°E Section B and 16°-25°E Section C) and three at the eastern end (49°-52°E Section D, 52°-61°E Section E and 61°-70°E Section F). Hydrothermal vents along the Sections B, C, E and F with thin oceanic crust are hosted by ultramafic rocks under tectonic-controlled magmatic-starved settings, and hydrothermal vents along the Section D are associated with exceed magmatism. Limited coverage of investigations is provided along the 35°-47°E SWIR (between Marion and Indomed fracture zones) and a lot of research has been done around the Bouvet Island, while no hydrothermal vents has been reported. Analyzing bathymetry, gravity and geochemical data, magmatism settings are favourable for the occurrence of hydrothermal systems along these two sections. An off-axial hydrothermal system in the southern flank of the SWIR that exhibits ultra-thin oceanic crust associated with an oceanic continental transition is postulated to exist along the 100-Ma slow-spreading isochron in the Enderby Basin. A discrete, denser enriched or less depleted mantle beneath the Antarctic Plate is an alternative explanation for the large scale thin oceanic crust concentrated on the southern flank of the SWIR.

The Varved Sediments of Lake Bosumtwi, Ghana and Implications for a new Chronology of West African Hydrologic Change During the Late Quaternary

NASA Astrophysics Data System (ADS)

Wheeler, C. W.; Overpeck, J. T.; Beck, J. W.; Arko, J.; Sharp, W. E.

2002-12-01

Lake Bosumtwi is a small (8-km diameter), deep (78-m) crater lake in the lowland forest of southern Ghana (West Africa) that offers tremendous potential for high-resolution environmental reconstruction. Lying in the path of the seasonal Intertropical Convergence Zone (ITCZ) monsoonal precipitation procession, as well as the dry Harmattan winds of the Sahel in winter, this lake is uniquely located to provide potential proxy records of these dominate climatic phenomena effecting West Africa's hydrologic cycle. The lake exhibits excellent sediment preservation, with finely laminated sediments through most of the ca. 24,000 years of core material recovered thus far. We present a detailed chronological analysis of the uppermost 1.1 meters of laminated sediment, obtained via a recently collected suite of freeze- and piston-cores. Utilizing digital images and petrographic thin-section transects of six freeze-cores and two piston cores, we identified 400 diagnostic marker laminations common among the cores, thus enabling cross correlation of the cores to a sub-centimeter scale. The marker laminations also serve as anchor points for counts of organic-rich fine-laminations that were hypothesized to be annual. Excellent agreement between our lamination counts and independent radiometric sediment age models (lead-210 and bomb radiocarbon) verify that these counted laminations are in fact annual (i.e. varves). Thus, we are able to present an annual chronology for the last 800 years of sedimentation (prior to 2000 AD)ñ ~4%. Though anthroprogenic changes have probably effected the local environment within the last 100 years, as we interpret anomalous increases in %organic carbon, %inorganic carbon and %nitrogen to indicate, the varve appearance does not seem to change across the 1.1 m section analyzed. Pre-nuclear weapon testing radiocarbon values, derived from bulk organic carbon, were examined in relation to the varve and lead-210 age-models to assess radiocarbon age offset due to reservoir effects and the redeposition of old-carbon; the data suggest that anomalously old radiocarbon ages ranging from ~430 to 3000 years are possible. The size of the radiocarbon bias may vary with lake status, indicating the role of old-carbon redeposition from ancient lake sediments currently at shallow depths or above current lake level in the crater catchment. Our study shows that 1) varves have excellent potential for creating a high-resolution chronology for Lake Bosumtwi, and 2) caution must be taken in using radiocarbon results to date the sediments of Lake Bosumtwi

Petrographic examination of carbonate aggregate prism specimens treated with chemical solutions normally occurring in Portland cement concrete.

DOT National Transportation Integrated Search

1979-01-01

The original rock prism specimens were prepared and the early length change data were taken as part of a Federal Highway Administration project on the behavior of carbonate aggregates in concrete. It had been shown that the length changes of the aggr...

Determination of Movement Sense in Mylonites.

ERIC Educational Resources Information Center

Simpson, Carol

1986-01-01

Describes how mylonite samples can be used to determine the sense of shear. Several sample collection techniques are presented. Criteria for shear sense determination are outlined and discussed so that they can be recognized and interpreted by students familiar with the use of a compass and a petrographic microscope. (TW)

Silicate petrography and origin of the mesosiderites: a preliminary investigation of their relationships to the howardite-eurite-diogenite suite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Floran, R. J

1978-04-01

Results are reported from a petrographic study of 20 mesosiderites that reveals that most contain a complex assemblage of mineral, lithic, and metal clasts. Mineral fragments dominate the clast population and consist primarily of orthopyroxene, plagioclase, and olivine.

Petrographic examination of concrete cores taken from the Ohio strategic highway research program (SHRP) specific pavement studies test road.

DOT National Transportation Integrated Search

2003-08-26

The 3-mile long SHRP pavement project is located on US 23, 25-miles north of Columbus, Ohio, : in Delaware County. Northbound lanes were constructed of portland cement concrete (PCC), : while southbound lanes were constructed of asphalt concrete (AC)...

Microstructural study of the polymorphic transformation in pentacene thin films.

PubMed

Murakami, Yosuke; Tomiya, Shigetaka; Koshitani, Naoki; Kudo, Yoshihiro; Satori, Kotaro; Itabashi, Masao; Kobayashi, Norihito; Nomoto, Kazumasa

2009-10-02

We have observed, by high-resolution cross-sectional transmission electron microscopy, the first direct evidence of polymorphic transformation in pentacene thin films deposited on silicon oxide substrates. Polymorphic transformation from the thin-film phase to the bulk phase occurred preferentially near polycrystalline grain boundaries, which exhibit concave surfaces. This process is thought to be driven by compressive stress caused by the grain boundaries. In addition to this stress, lattice mismatch between the two phases also results in structural defect formation.

Standard-, Reduced-, and No-Dose Thin-Section Radiologic Examinations: Comparison of Capability for Nodule Detection and Nodule Type Assessment in Patients Suspected of Having Pulmonary Nodules.

PubMed

Ohno, Yoshiharu; Koyama, Hisanobu; Yoshikawa, Takeshi; Kishida, Yuji; Seki, Shinichiro; Takenaka, Daisuke; Yui, Masao; Miyazaki, Mitsue; Sugimura, Kazuro

2017-08-01

Purpose To compare the capability of pulmonary thin-section magnetic resonance (MR) imaging with ultrashort echo time (UTE) with that of standard- and reduced-dose thin-section computed tomography (CT) in nodule detection and evaluation of nodule type. Materials and Methods The institutional review board approved this study, and written informed consent was obtained from each patient. Standard- and reduced-dose chest CT (60 and 250 mA) and MR imaging with UTE were used to examine 52 patients; 29 were men (mean age, 66.4 years ± 7.3 [standard deviation]; age range, 48-79 years) and 23 were women (mean age, 64.8 years ± 10.1; age range, 42-83 years). Probability of nodule presence was assessed for all methods with a five-point visual scoring system. All nodules were then classified as missed, ground-glass, part-solid, or solid nodules. To compare nodule detection capability of the three methods, consensus for performances was rated by using jackknife free-response receiver operating characteristic analysis, and κ analysis was used to compare intermethod agreement for nodule type classification. Results There was no significant difference (F = 0.70, P = .59) in figure of merit between methods (standard-dose CT, 0.86; reduced-dose CT, 0.84; MR imaging with UTE, 0.86). There was no significant difference in sensitivity between methods (standard-dose CT vs reduced-dose CT, P = .50; standard-dose CT vs MR imaging with UTE, P = .50; reduced-dose CT vs MR imaging with UTE, P >.99). Intermethod agreement was excellent (standard-dose CT vs reduced-dose CT, κ = 0.98, P < .001; standard-dose CT vs MR imaging with UTE, κ = 0.98, P < .001; reduced-dose CT vs MR imaging with UTE, κ = 0.99, P < .001). Conclusion Pulmonary thin-section MR imaging with UTE was useful in nodule detection and evaluation of nodule type, and it is considered at least as efficacious as standard- or reduced-dose thin-section CT. © RSNA, 2017 Online supplemental material is available for this article.

Transverse vibrations of shear-deformable beams using a general higher order theory

NASA Technical Reports Server (NTRS)

Kosmatka, J. B.

1993-01-01

A general higher order theory is developed to study the static and vibrational behavior of beam structures having an arbitrary cross section that utilizes both out-of-plane shear-dependent warping and in-plane (anticlastic) deformations. The equations of motion are derived via Hamilton's principle, where the full 3D constitutive relations are used. A simplified version of the general higher-order theory is also presented for beams having an arbitrary cross section that includes out-of-plane shear deformation but assumes that stresses within the cross section and in-plane deformations are negligible. This simplified model, which is accurate for long to moderately short wavelengths, offers substantial improvements over existing higher order theories that are limited to beams with thin rectangular cross sections. The current approach will be very useful in the study of thin-wall closed-cell beams such as airfoil-type sections where the magnitude of shear-related cross-sectional warping is significant.

1. GORGE HIGH DAM. THIS THIN ARCH DAM WITH A ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. GORGE HIGH DAM. THIS THIN ARCH DAM WITH A GRAVITY SECTION IS THE THIRD DAM BUILT BY SEATTLE CITY LIGHT TO PROVIDE WATER FOR GORGE POWERHOUSE AND WAS COMPLETED IN 1961, 1989. - Skagit Power Development, Gorge High Dam, On Skagit River, 2.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

Basic Principles of Thin-Walled Open Bars Taking into Account Where Influence Shifts of Cross Sections are Concerned

NASA Astrophysics Data System (ADS)

Panasenko, N. N.; Sinelschikov, A. V.

2017-11-01

The finite element method is considered to be the most effective in relation to the calculation of strength and stability of buildings and engineering constructions. As a rule, for the modelling of supporting 3-D frameworks, finite elements with six degrees of freedom are used in each of the nodes. In practice, such supporting frameworks represent the thin-walled welded bars and hot-rolled bars of open and closed profiles in which cross-sectional deplanation must be taken into account. This idea was first introduced by L N Vorobjev and brought to one of the easiest variants of the thin-walled bar theory. The development of this approach is based on taking into account the middle surface shear deformation and adding the deformations of a thin-walled open bar to the formulas for potential and kinetic energy; these deformations depend on shearing stress and result in decreasing the frequency of the first tone of fluctuations to 13%. The authors of the article recommend taking into account this fact when calculating fail-proof dynamic systems.

Examination of the influence of coatings on thin superalloy sections. Volume 2: Detailed procedures and data. [corrosion resistance

NASA Technical Reports Server (NTRS)

Kaufman, M.

1974-01-01

The effects of an aluminide coating, Codep B-1, and of section thickness were investigated on two cast nickel base superalloys, Rene 80 and Rene 120. Cast section thicknesses ranged from 0.038 cm to 0.15 cm. Simulated engine exposures for 1000 hours at 899C or 982C in a jet fuel burner rig with cyclic air cooling were studied, as were the effects of surface machining before coating and re-machining and re-coating after exposures. The properties evaluated included tensile at room temperature., 871C and 982C, stress rupture at 760C, 871C, 982C and 1093C, high cycle mechanical fatigue at room temperature., and thermal fatigue with a 1093C peak temperature. Thin sections had tensile strengths similar to standard size bars up to 871C and lower strengths at 982C and above, with equivalent elongation, and stress rupture life was lower for thin sections at all test conditions. The aluminide coating lowered tensile and rupture strengths up to 871C, with greater effects on thinner specimens. Elevated temperature exposure lowered tensile and rupture strengths of thinner specimens at the lower test temperatures. Surface machining had little effect on properties, but re-machining after exposure reduced thickness and increased metallurgical changes enough to lower properties at most test conditions.

Thin HSIL of the Cervix: Detecting a Variant of High-grade Squamous Intraepithelial Lesions With a p16INK4a Antibody.

PubMed

Reich, Olaf; Regauer, Sigrid

2017-01-01

The WHO defines thin high-grade squamous intraepithelial lesions (HSIL) as a high-grade intraepithelial lesion of the cervix that is usually ≤9 cells thick. These lesions usually develop in early metaplastic squamous epithelium without anteceding low-grade squamous intraepithelial lesions (LSIL). The prevalence of thin HSIL is not well documented. We evaluated different characteristics of thin HSIL at time of treatment. We studied 25 formalin-fixed and paraffin-embedded conization specimens processed as step-serial sections. HSIL≤9 cells thick were classified as thin HSIL. HSIL≥10 cells thick were classified as classic HSIL. Immunohistochemical p16 staining was used to confirm lesions of thin HSIL. Overall, 19 (76%) specimens contained both thin HSIL and classic HSIL, 4 (16%) contained thin HSIL only, 1 (4%) contained classic-type HSIL only, and 1 (4%) contained thin HSIL and LSIL. Thin HSILs developed in both the columnar surface epithelium and deep cervical glandular epithelium. Most thin HSILs were 5 cells thick. All HSILs (thin and classic) were located inside the transformation zone and had a median horizontal extension of 8 mm (range, 0.3 to 21 mm). Our findings suggest that thin HSILs are frequent findings, that they coexist with classic HSIL, and preferably arise in the exposed parts of the transformation zone including the glandular crypts.

Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry.

PubMed

Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J; Kertesz, Vilmos; Gan, Jinping

2016-03-25

Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites were studied. Major organs (brain, lung, liver, kidney and muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed the same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. In addition, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement. Copyright © 2015 Elsevier B.V. All rights reserved.

Zinc isotope ratio imaging of rat brain thin sections from stable isotope tracer studies by LA-MC-ICP-MS.

PubMed

Urgast, Dagmar S; Hill, Sarah; Kwun, In-Sook; Beattie, John H; Goenaga-Infante, Heidi; Feldmann, Jörg

2012-10-01

Zinc stable isotope tracers (⁶⁷Zn and ⁷⁰Zn) were injected into rats at two different time points to investigate the feasibility of using tracers to study zinc kinetics at the microscale within distinct tissue features. Laser ablation coupled to multi-collector ICP-MS was used to analyse average isotope ratios in liver thin sections and to generate bio-images showing zinc isotope ratio distribution in brain thin sections. Average isotope ratios of all samples from treated animals were found to be statistically different (P < 0.05) from samples from untreated control animals. Furthermore, differing isotope ratios in physiological features of the brain, namely hippocampus, amygdala, cortex and hypothalamus, were identified. This indicates that these regions differ in their zinc metabolism kinetics. While cortex and hypothalamus contain more tracer two days after injection than 14 days after injection, the opposite is true for hippocampus and amygdala. This study showed that stable isotope tracer experiments can be combined with laser ablation MC-ICP-MS to measure trace element kinetics in tissues at a microscale level.

Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

DOE PAGES

Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J.; ...

2015-11-03

Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites was studied. Major organs (brain, lung, liver, kidney, muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed themore » same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. Furthermore, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement.« less

Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J.

Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites was studied. Major organs (brain, lung, liver, kidney, muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed themore » same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. Furthermore, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement.« less

Dual-Beam Sample Preparation | Materials Science | NREL

Science.gov Websites

images showing cutting of trenches to remove a wafer section and transferring that section to a grid post section and transferring that section to a grid post. Here the wafer section is lifted out and seen from , extracted from the wafer then transferred and welded to a TEM grid post. Final thinning down to a thickness

Use of a thin-section archive and enterprise 3D software for long-term storage of thin-slice CT data sets.

PubMed

Meenan, Christopher; Daly, Barry; Toland, Christopher; Nagy, Paul

2006-01-01

Rapid advances are changing the technology and applications of multidetector computed tomography (CT) scanners. The major increase in data associated with this new technology, however, breaks most commercial picture archiving and communication system (PACS) architectures by preventing them from delivering data in real time to radiologists and outside clinicians. We proposed a phased model for 3D workflow, installed a thin-slice archive and measured thin-slice data storage over a period of 5 months. A mean of 1,869 CT studies were stored per month, with an average of 643 images per study and a mean total volume of 588 GB/month. We also surveyed 48 radiologists to determine diagnostic use, impressions of thin-slice value, and requirements for retention times. The majority of radiologists thought thin slice was helpful for diagnosis and regularly used the application. Permanent storage of thin slice CT is likely to become best practice and a mission-critical pursuit for the health care enterprise.

Using Cf-252 for single event upset testing

NASA Astrophysics Data System (ADS)

Howard, J. W.; Chen, R.; Block, R. C.; Becker, M.; Costantine, A. G.; Smith, L. S.; Soli, G. A.; Stauber, M. C.

An improved system using Cf-252 and associated nuclear instrumentation has been used to determine single event upset (SEU) cross section versus linear energy transfer (LET) curve for several static random access memory (SRAM) devices. Through the use of a thin-film scintillator, providing energy information on each fission fragment, individual SEU's and ion energy can be associated to calculate the cross section curves. Results are presented from tests of several SRAM's over the 17-43 MeV-cm squared/mg LET range. Values obtained for SEU cross sections and LET thresholds are in good agreement with the results from accelerator testing. The equipment is described, the theory of thin-film scintillation detector response is summarized, experimental procedures are reviewed, and the test results are discussed.

Optical limiting properties of optically active phthalocyanine derivatives

NASA Astrophysics Data System (ADS)

Wang, Peng; Zhang, Shuang; Wu, Peiji; Ye, Cheng; Liu, Hongwei; Xi, Fu

2001-06-01

The optical limiting properties of four optically active phthalocyanine derivatives in chloroform solutions and epoxy resin thin plates were measured at 532 nm with 10 ns pulses. The excited state absorption cross-section σex and refractive-index cross-section σr were determined with the Z-scan technique. These chromophores possess larger σex than the ground state absorption cross-section σ0, indicating that they are the potential materials for reverse saturable absorption (RSA). The negative σr values of these chromophores add to the thermal contribution, producing a larger defocusing effect, which may be helpful in further enhancing their optical limiting performance. The optical limiting responses of the thin plate samples are stronger than those of the chloroform solutions.

Construction and monitoring of thin overlay and crack sealant test sections at the Pecos test track.

DOT National Transportation Integrated Search

2014-10-01

In this project, several crack sealant sections were constructed at the Pecos RTC. Six different sealants were : applied in routed and non-routed configurations on both older and newer pavement. The following summer, : the sections were revaluated in...

Fabrication and characterization of lead-free BaTiO3 thin film for storage device applications

NASA Astrophysics Data System (ADS)

Sharma, Hakikat; Negi, N. S.

2018-05-01

The lead-free BaTiO3 (BT) thin film solution has been prepared by sol-gel method. The prepared solution spin coated on Pt/TiO2/SiO2/ Si substrate. The fabricated thin film was analyzed by XRD and Raman spectrometer for structural conformation. Uniformity of thin film was examined by Atomic force microscope (AFM). Thickness of the film was measured by cross sectional FESEM. Activation energies for both positive and negative biasing have been calculated from temperature dependent leakage current density as a function of electric field. For ferroelectric memory devices such as FRAM the hysteresis loop plays important role. Electric filed dependent polarization of BT thin film measured at different switching voltages. With increasing voltage maximum polarization increases.

Shear thinning effects on blood flow in straight and curved tubes

NASA Astrophysics Data System (ADS)

Cherry, Erica M.; Eaton, John K.

2013-07-01

Simulations were performed to determine the magnitude and types of errors one can expect when approximating blood in large arteries as a Newtonian fluid, particularly in the presence of secondary flows. This was accomplished by running steady simulations of blood flow in straight and curved tubes using both Newtonian and shear-thinning viscosity models. In the shear-thinning simulations, the viscosity was modeled as a shear rate-dependent function fit to experimental data. Simulations in straight tubes were modeled after physiologically relevant arterial flows, and flow parameters for the curved tube simulations were chosen to examine a variety of secondary flow strengths. The diameters ranged from 1 mm to 10 mm and the Reynolds numbers from 24 to 1500. Pressure and velocity data are reported for all simulations. In the straight tube simulations, the shear-thinning flows had flattened velocity profiles and higher pressure gradients compared to the Newtonian simulations. In the curved tube flows, the shear-thinning simulations tended to have blunted axial velocity profiles, decreased secondary flow strengths, and decreased axial vorticity compared to the Newtonian simulations. The cross-sectionally averaged pressure drops in the curved tubes were higher in the shear-thinning flows at low Reynolds number but lower at high Reynolds number. The maximum deviation in secondary flow magnitude averaged over the cross sectional area was 19% of the maximum secondary flow and the maximum deviation in axial vorticity was 25% of the maximum vorticity.

Variable Sources and Differentiation of Lavas from the Copahue-Caviahue Eruptive Complex, Neuquen Argentina

NASA Astrophysics Data System (ADS)

Todd, E.; Ort, M. H.

2012-12-01

Caldera collapse (˜180 km2) associated with a large Pliocene pyroclastic eruption and subsequent glacial erosion exposed an extensive and complex cross-section of pre-caldera volcanic history (at least 5 My) at the Copahue-Caviahue Eruptive Center (CCEC) in the Andean Southern Volcanic Zone (SVZ) of Argentina. Lava flows in wall exposures range from olivine-rich basaltic andesite to trachyte, are typically horizontal, vary in abundance and thickness at different wall exposures, and rarely correlate with flows in adjacent sections, although some lava and pyroclastic deposits from adjacent sections are similar in petrography, mineral assemblage, and geochemistry. Bulk-rock geochemical and isotopic data indicate at least two distinct primary melt types contributed to pre-caldera CCEC volcanism, and their differentiates produced a high-K and a low-K series. Incompatible element and isotope systematics suggest they are not related by differentiation of a common parental melt, and less-evolved examples of both types occur throughout the pre-caldera stratigraphic section, suggesting long-lived recharge of the local system by variably-sourced magmas. Petrographic and mineral chemistry evidence indicates that mixing of dissimilar magma types produced compositionally intermediate magmas. The location of the CCEC, rear of the volcanic front (VF), yet trenchward of regional backarc basin (BAB) volcanism, is reflected by the composition of CCEC lavas, which are transitional between local VF and BAB types. Thus, contrasting low- and high-K CCEC magmas in the SVZ rear-arc may reflect local focusing of VF-like (low-K) and BAB-like (high-K) melts.

Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville B core, Chesapeake Bay impact structure, USA

USGS Publications Warehouse

Townsend, G.N.; Gibson, R.L.; Horton, J. Wright; Reimold, W.U.; Schmitt, R.T.; Bartosova, K.

2009-01-01

The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite-graphite ?? fibrolite ?? garnet ?? tourmaline ?? pyrite ?? rutile ?? pyrrhotite mica schist, hornblende-plagioclase-epidote-biotite- K-feldspar-quartz-titanite-calcite amphibolite, and vesuvianite-plagioclase- quartz-epidote calc-silicate rock) are dominant in the upper part of the lower basement-derived section, and they are intruded by pegmatitic to coarse-grained granite (K-feldspar-plagioclase-quartz-muscovite ?? biotite ?? garnet) that increases in volume proportion downward. The granite megablock contains both gneissic and weakly or nonfoliated biotite granite varieties (K-feldspar-quartz-plagioclase-biotite ?? muscovite ?? pyrite), with small schist xenoliths consisting of biotite-plagioclase-quartz ?? epidote ?? amphibole. The lower basement-derived section and both megablocks exhibit similar middleto upper-amphibolite-facies metamorphic grades that suggest they might represent parts of a single terrane. However, the mica schists in the lower basement-derived sequence and in the megablock xenoliths show differences in both mineralogy and whole-rock chemistry that suggest a more mafi c source for the xenoliths. Similarly, the mineralogy of the amphibolite in the lower basement-derived section and its association with calc-silicate rock suggest a sedimentary protolith, whereas the bulk-rock and mineral chemistry of the megablock amphibolite indicate an igneous protolith. The lower basement-derived granite also shows bulk chemical and mineralogical differences from the megablock gneissic and biotite granites. ?? 2009 The Geological Society of America.

Investigation of interfacial fracture behavior on injection molded parts

NASA Astrophysics Data System (ADS)

Fischer, Matthieu; Ausias, Gilles; Kuehnert, Ines

2016-03-01

In this study the interfacial morphology of different polymers joined by various assembly injection molding (AIM) technologies were discussed. Melt streams were injected successively using tools with core-back or rotation techniques. To compare bulk specimen strength and weld line strength, the fracture behavior of different specimen scales and thin sections were investigated. An in-situ SEM tensile test and a new thin section testing device which is used in polarized (transmitted) light microscopy were used to observe specimen failure. The effects of processing on spherulitic structures were linked to bonding strength and mechanical properties.

Sedimentary petrology and reservoir quality of the Middle Jurassic Red Glacier Formation, Cook Inlet forearc basin: Initial impressions

USGS Publications Warehouse

Helmold, K.P.; LePain, D.L.; Stanley, Richard G.

2016-01-01

The Division of Geological & Geophysical Surveys and Division of Oil & Gas are currently conducting a study of the hydrocarbon potential of Cook Inlet forearc basin (Gillis, 2013, 2014; LePain and others, 2013; Wartes, 2015; Herriott, 2016 [this volume]). The Middle Jurassic Tuxedni Group is recognized as a major source of oil in Tertiary reservoirs (Magoon, 1994), although the potential for Tuxedni reservoirs remains largely unknown. As part of this program, five days of the 2015 field season were spent examining outcrops, largely sandstones, of the Middle Jurassic Red Glacier Formation (Tuxedni Group) approximately 6.4 km northeast of Johnson Glacier on the western side of Cook Inlet (fig. 4-1). Three stratigraphic sections (fig. 4-2) totaling approximately 307 m in thickness were measured and described in detail (LePain and others, 2016 [this volume]). Samples were collected for a variety of analyses including palynology, Rock-Eval pyrolysis, vitrinite reflectance, detrital zircon geochronology, and petrology. This report summarizes our initial impressions of the petrology and reservoir quality of sandstones encountered in these measured sections. Interpretations are based largely on hand-lens observations of hand specimens and are augmented by stereomicroscope observations. Detailed petrographic (point-count) analyses and measurement of petrophysical properties (porosity, permeability, and grain density) are currently in progress.

Thin film memory matrix using amorphous and high resistive layers

NASA Technical Reports Server (NTRS)

Thakoor, Anilkumar P. (Inventor); Lambe, John (Inventor); Moopen, Alexander (Inventor)

1989-01-01

Memory cells in a matrix are provided by a thin film of amorphous semiconductor material overlayed by a thin film of resistive material. An array of parallel conductors on one side perpendicular to an array of parallel conductors on the other side enable the amorphous semiconductor material to be switched in addressed areas to be switched from a high resistance state to a low resistance state with a predetermined level of electrical energy applied through selected conductors, and thereafter to be read out with a lower level of electrical energy. Each cell may be fabricated in the channel of an MIS field-effect transistor with a separate common gate over each section to enable the memory matrix to be selectively blanked in sections during storing or reading out of data. This allows for time sharing of addressing circuitry for storing and reading out data in a synaptic network, which may be under control of a microprocessor.

Dynamical evidence regarding the relationship between asteroids and meteorites

NASA Technical Reports Server (NTRS)

Wetherill, G. W.

1978-01-01

Meteorites are fragments of small solar system bodies transferring into the vicinity of earth from the inner edge of the asteroid belt. Photometric measurements support an association between Apollo objects and chondritic meteorites. Dynamical arguments indicate that most Apollo objects are devolatilized comet residues, however; petrographic and cosmogonical reasons argue against this conclusion.

Studies on rock characteristics and timing of creep at selected landslide sites in Taiwan

Treesearch

Cheng-Yi Lee

2000-01-01

A study was conducted to investigate the causes of and rock characteristics at three landslide sites in the Tesngwen Reservoir watershed of southern Taiwan. Research methods used included the petrographic microscope, X-ray diffraction (XRD), scanning electron microscope (SEM), inductively coupled plasma spectroscope (ICP), constant head permeameter in triaxial...

Unambiguous Spectral Evidence for High- (and Low-) Calcium Pyroxene in Asteroids and Meteorites

NASA Technical Reports Server (NTRS)

Sunshine, J. M.; Bus, S. J.; Burbine, T. H.; McCoy, T. J.; Binzel, R. P.

2002-01-01

Several new S-asteroid spectra are modeled and found to contain both low- and high-calcium pyroxenes. Similar results are obtained for spectra of eucrites. Their inferred mineralogy is very consistent with petrographic results, lending confidence to the asteroid analyses. Additional information is contained in the original extended abstract.

Statistical Analysis of Geomorphic, Petrographic and Structural Characteristics of the Dartmoor Tors, Southwest England

DTIC Science & Technology

1993-05-01

slightly warmer than that of today, followed by periglacial removal of the weathered debris (Linton, 1955). The Dartmoor granite, which covers...and the distribution of its detritus in the sediments of southern England. Quarterly Journal of the Geological Society of London, vol. 87, pp. 62-96

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The first part covers standards for gaseous fuels. The standard part covers standards on coal and coke including the classification of coals, determination of major elements in coal ash and trace elements in coal, metallurgical properties of coal and coke, methods of analysis of coal and coke, petrographic analysis of coal and coke, physical characteristics of coal, quality assurance and sampling.

Stable Magnesium Isotope Variation in Melilite Mantle of Allende Type B1 CAI EK 459-5-1

NASA Technical Reports Server (NTRS)

Kerekgyarto, A. G.; Jeffcoat, C. R.; Lapen, T. J.; Andreasen, R.; Righter, M.; Ross, D. K.

2014-01-01

Ca-Al-rich inclusions (CAIs) are the earliest formed crystalline material in our solar system and they record early Solar System processes. Here we present petrographic and delta Mg-25 data of melilite mantles in a Type B1 CAI that records early solar nebular processes.

Crystallographic Study of Itokawa Particle, RA-QD02-0127 by Using Energy-Scanning X-Ray Diffraction Method with Synchrotron Radiation

NASA Technical Reports Server (NTRS)

Hagiya, K.; Ohsumi, K.; Komatsu, M.; Mikouchi, T.; Zolensky, M. E.; Hirata, A.; Yamaguchi, S.; Kurokawa, A.

2016-01-01

The petrographic study of Itokawa particle, RA-QD02-0127 has been performed by SEM-EDS and optical microscope observations. The purpose of this study is to understand better the metamorphic and impact shock history of asteroid Itokawa, and other S-class asteroids.

Carbon dioxide and methane sorption in high volatile bituminous coals from Indiana, USA

USGS Publications Warehouse

Mastalerz, Maria; Gluskoter, Harold J.; Rupp, J.

2004-01-01

Samples of coals from several coalbeds in Indiana were analyzed for CO2 and CH4 sorption capacity using a high-pressure adsorption isotherm technique. Coal quality and petrographic composition of the coals were determined to study their relationships to the volume of CO2 and CH4 that could be sorbed into the coal. At the temperature of 17 ??C and 400 psi (??? 2.8 MPa), the coals can sorb (on dry ash-free basis) from 4 to 6.3 m3/ton (128-202 scf/ton) of CH4 and 19.5-24.6 m3/ton4 (624 to 788 scf/ton) of CO2. The ratio of CO2/CH4 at these conditions ranges from 3.5 to 5.3 and decreases with an increasing pressure for all coals. The coals studied are of a very similar coal rank (Ro from 0.48 to 0.62%) but of varying petrographic composition, and CO2 sorption volumes appear to be positively correlated to the content of maceral telocollinite. ?? 2004 Elsevier B.V. All rights reserved.

Evidence for magma mixing within the Laacher See magma chamber (East Eifel, Germany)

USGS Publications Warehouse

Worner, G.; Wright, T.L.

1984-01-01

The final pyroclastic products of the late Quaternary phonolitic Laacher See volcano (East Eifel, W.-Germany) range from feldspar-rich gray phonolite to dark olivine-bearing rocks with variable amounts of feldspar and Al-augite megacrysts. Petrographically and chemically homogeneous clasts occur along with composite lapilli spanning the compositional range from phonolite (MgO 0.9%) to mafic hybrid rock (MgO 7.0%) for all major and trace elements. Both a basanitic and a phonolitic phenocryst paragenesis occur within individual clasts. The phonolite-derived phenocrysts are characterized by glass inclusions of evolved composition, rare inverse zoning and strong resorption indicating disequilibrium with the mafic hybrid matrix. Basanitic (magnesian) clinopyroxene and olivine, in contrast, show skeletal (normally zoned) overgrowths indicative of post-mixing crystallization. In accord with petrographical and other chemical evidence, mass balance calculations suggest mixing of an evolved Laacher See phonolite containing variable amounts of mineral cumulates and a megacryst-bearing basanite magma. Magma mixing occurred just prior to eruption (hours) of the lowermost magma layer of the Laacher See magma chamber but did not trigger the volcanic activity. ?? 1984.

Lithospheric mantle beneath the south-eastern Siberian craton: petrology of peridotite xenoliths in basalts from the Tokinsky Stanovik

NASA Astrophysics Data System (ADS)

Ionov, Dmitri A.; Prikhodko, Vladimir S.; Bodinier, Jean-Louis; Sobolev, Alexander V.; Weis, Dominique

2005-08-01

We provide petrographic, major and trace element data for over 30 spinel peridotite xenoliths from the Tokinsky Stanovik (Tok) volcanic field on the Aldan shield to characterize the lithospheric mantle beneath the south-eastern margin of the Siberian craton, which formed in the Mesoproterozoic. High equilibration temperatures (870 1,010°C) of the xenoliths and the absence of garnet-bearing peridotites indicate a much thinner lithosphere than in the central craton. Most common among the xenoliths are clinopyroxene-poor lherzolites and harzburgites with Al2O3 and CaO contents nearly as low as in refractory xenoliths from kimberlite pipes (Mir, Udachnaya) in the central and northern Siberian craton. By contrast, the Tok peridotites have higher FeO, lower Mg-numbers and lower modal orthopyroxene and are apparently formed by shallow partial melting (≤3 GPa). Nearly all Tok xenoliths yield petrographic and chemical evidence for metasomatism: accessory phlogopite, amphibole, phosphates, feldspar and Ti-rich oxides, very high Na2O (2 3.1%) in clinopyroxene, LREE enrichments in whole-rocks.

Rb-Sr and Sm-Nd Studies of Olivine-Phyric Shergottites RBT 04262 and LAR 06319: Isotopic Evidence for Relationship to Enriched Basaltic Shergottites

NASA Technical Reports Server (NTRS)

Nyquist, L.E.; Shih, C.-Y.; Reese, Y.

2009-01-01

RBT 04262 and LAR 06319 are two Martian meteorites recently discovered in Antarctica. Both contain abundant olivines, and were classified as olivine-phyric shergottites. A detailed petrographic study of RBT 04262 suggested it should be reclassified as a lherzolitic shergottite. However, the moderately LREE-depleted REE distribution pattern indicated that it is closely related to enriched basaltic shergottites like Shergotty, Zagami, Los Angeles, etc. In earlier studies of a similarly olivinephyric shergottite NWA 1068 which contains 21% modal olivine, it was shown that it probably was produced from an enriched basaltic shergottite magma by olivine accumulation . As for LAR 06319, recent petrographic studies suggested that it is different from either lherzolitic shergottites or the highly LREE-depleted olivine-phyric shergottites. We performed Rb-Sr and Sm-Nd isotopic analyses on RBT 04262 and LAR 06319 to determine their crystallization ages and Sr and Nd isotopic signatures, and to better understand the petrogenetic relationships between them and other basaltic, lherzolitic and depleted olivine-phyric shergottites.

Twisting of thin walled columns perfectly restrained at one end

NASA Technical Reports Server (NTRS)

Lazzarino, Lucio

1938-01-01

Proceeding from the basic assumptions of the Batho-Bredt theory on twisting failure of thin-walled columns, the discrepancies most frequently encountered are analyzed. A generalized approximate method is suggested for the determination of the disturbances in the stress condition of the column, induced by the constrained warping in one of the end sections.

Cutting thin sections of bone

NASA Technical Reports Server (NTRS)

Ashley, W. W.

1972-01-01

Medical equipment for obtaining repetitive planoparallel sections of bone to study healing of bone structure under high gravity stress is described. Device consists of modified saw with diamond cutting edges. Construction of device and manner of use are explained.

Ultrastructural identification of noradrenergic nerve terminals and vasopressin-containing neurons of the paraventricular nucleus in the same thin section.

PubMed

Silverman, A J; Hou-Yu, A; Oldfield, B J

1983-09-01

Since many peptidergic cell groups receive a diverse and complex monoaminergic innervation, we have developed a double-label procedure to visualize a peptide and a catecholamine in the same ultrathin section. Radiolabeled norepinephrine (NE) is applied locally and its reuptake into NE terminals is demonstrated by ultrastructural radioautography. Controls in this and other studies demonstrate that the NE labels only NE (and possibly epinephrine) terminals and not dopaminergic or serotonergic terminals. In the same tissue, vasopressin is localized by immunocytochemistry on unembedded sections that are subsequently embedded in epoxy resins for thin sectioning. The procedure as described here shows that NE terminals in the periventricular zone of the paraventricular nucleus of the hypothalamus innervate both vasopressin-positive and vasopressin-negative structures. This technique is useful in determining the chemical connectivity of the hypothalamus.

The aerodynamic properties of thick aerofoils suitable for internal bracing

NASA Technical Reports Server (NTRS)

Norton, F H

1920-01-01

The object of this investigation was to determine the characteristics of various types of wings having sufficient depth to entirely inclose the wing bracing, and also to provide data for the further design of such sections. This type of wing is of interest because it eliminates the resistance of the interplane bracing, a portion of the airplane that sometimes absorbs one-quarter of the total power required to fly, and because these wings may be made to give a very high maximum lift. Results of the investigation of the following subjects are given: (1) effect of changing the upper and lower camber of thick aerofoils of uniform section; (2) effect of thickening the center and thinning the tips of a thin aerofoil; (3) effect of adding a convex lower surface to a tapered section; (4) effect of changing the mean thickness with constant center and tip sections; and (5) effect of varying the chord along the span.

Theory of thin-walled rods

NASA Technical Reports Server (NTRS)

Goldenveizer, A L

1951-01-01

Starting with the Love equations for bending of extensible shells, "principal stress states" are sought for a thin-walled rod of arbitrary but open cross section. Principal stress states exclude those local states arising from end conditions which damp out with distance from the ends. It is found that for rods of intermediate length, long enough to avoid local bending at a support, and short enough that elementary torsion and bending are not the most significant stress states, four principal states exist. Three of these states are associated with the planar distribution of axial stress and are equivalent to the engineering theory of extension and bending of solid sections. The fourth state resembles that which has been called in the literature "bending stress due to torsional", except that cross sections are permitted to bend and the shear along the center line of the cross section is permitted to differ from zero.

The Processing and Mechanical Properties of High Temperature/High Performance Composites. Book 1, Section 1: Coatings and Interfaces

DTIC Science & Technology

1989-10-15

Cut Prestressed Film H.M. Jensen on a Substrate J.W. Hutchinson K.S. Kim 8. Measuring the Strength and Stiffness T.P. Weihs of Thin Film Materials by...for Thin Films T.P. Weihs Using Micro-Cantilever Beams J.C. Bravman W.D. Nix 10. Analysis of Elastic and Plastic Deformation A.K. Bhattacharya...Associated with Indentation Testing of Thin W.D. Nix Films on Substrates 11. Finite Elenent Simulidion of Indentation A.K. 13hattacharya Experimnents W.D

Low-head feeding system for thin section castings

DOEpatents

Daniel, Sabah S.; Kleeb, Thomas R.; Lewis, Thomas W.; McDermott, John F.; Ozgu, Mustafa R.; Padfield, Ralph C.; Rego, Donovan N.; Vassilicos, Achilles

1990-01-01

A feed system is provided for conveying molten metal to a thin section caster having mold surfaces moving exclusively in the direction of casting. The feed system has a passage of circular cross section adjacent to one end thereof for receiving molten metal and a rectangular cross section at the delivery end thereof adjacent to the caster. The feed system is designed for supplying molten metal to the caster at low pressure for "closed-pool" type caster operation. The point of highest elevation in the metal flow passage of the feed system is on the upper surface of a transition portion where the cross section changes from circular to rectangular adjacent to the nozzle. The level or height of the high point above the centerline of the nozzle exit is selected so as to be less than the pressure of the metal measured in inches at the nozzle exit. This feature enables the maintenance of positive pressure in the metal within the feed system so that ingress of air into the metal is prevented.

Clinical, pathological and thin-section CT features of persistent multiple ground-glass opacity nodules: comparison with solitary ground-glass opacity nodule.

PubMed

Kim, Tae Jung; Goo, Jin Mo; Lee, Kyung Won; Park, Chang Min; Lee, Hyun Ju

2009-05-01

To retrospectively compare the clinical, pathological, and thin-section CT features of persistent multiple ground-glass opacity (GGO) nodules with those of solitary GGO nodules. Histopathologic specimens were obtained from 193 GGO nodules in 136 patients (87 women, 49 men; mean age, 57; age range 33-81). The clinical data, pathologic findings, and thin-section CT features of multiple and solitary GGO nodules were compared by using t-test or Fisher's exact test. Multiple GGO nodules (n=105) included atypical adenomatous hyperplasia (AAH) (n=31), bronchioloalveolar carcinoma (BAC) (n=33), adenocarcinoma (n=34) and focal interstitial fibrosis (n=7). Solitary GGO nodules included AAH (n=8), BAC (n=15), adenocarcinoma (n=55) and focal interstitial fibrosis (n=10). AAH (P=.001) and BAC (P=.029) were more frequent in multiple GGO nodules, whereas adenocarcinoma (P<.001) was more frequent in solitary GGO nodules. Female sex (P<.001), nonsmoker (P=.012) and multiple primary lung cancers (P<.001) were more frequent for multiple GGO nodules, which were smaller (12 mm+/-7.9) than solitary GGO nodules (17 mm+/-8.1) (P<.001). Air-bronchogram (P=.019), bubble-lucency (P=.004), and pleural retraction (P<.001) were more frequent in solitary GGO nodules. There was no postoperative recurrence except for one patient with multiple GGO nodules and one with solitary GGO nodule. Clinical, pathological, and thin-section CT features of persistent multiple GGO nodules were found to differ from those of solitary GGO nodules. Nevertheless, the two nodule types can probably be followed up and managed in a similar manner because their prognoses were found to be similar.

Provenance, diagenesis, tectonic setting and reservoir quality of the sandstones of the Kareem Formation, Gulf of Suez, Egypt

NASA Astrophysics Data System (ADS)

Zaid, Samir M.

2013-09-01

The Middle Miocene Kareem sandstones are important oil reservoirs in the southwestern part of the Gulf of Suez basin, Egypt. However, their diagenesis and provenance and their impact on reservoir quality, are virtually unknown. Samples from the Zeit Bay Oil Field, and the East Zeit Oil Field represent the Lower Kareem (Rahmi Member) and the Upper Kareem (Shagar Member), were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower Rahmi sandstones have an average framework composition of Q95F3.4R1.6, and 90% of the quartz grains are monocrystalline. By contrast, the Upper Shagar sandstones are only slightly less quartzose with an average framework composition of Q76F21R3 and 82% of the quartz grains are monocrystalline. The Kareem sandstones are mostly quartzarenite with subordinate subarkose and arkose. Petrographical and geochemical data of sandstones indicate that they were derived from granitic and metamorphic terrains as the main source rock with a subordinate quartzose recycled sedimentary rocks and deposited in a passive continental margin of a syn rift basin. The sandstones of the Kareem Formation show upward decrease in maturity. Petrographic study revealed that dolomite is the dominant cement and generally occurs as fine to medium rhombs pore occluding phase and locally as a grain replacive phase. Authigenic quartz occurs as small euhedral crystals, locally as large pyramidal crystals in the primary pores. Authigenic anhydrites typically occur as poikilotopic rhombs or elongate laths infilling pores but also as vein filling cement. The kaolinite is a by-product of feldspar leaching in the presence of acidic fluid produced during the maturation of organic matter in the adjacent Miocene rocks. Diagenetic features include compaction; dolomite, silica and anhydrite cementation with minor iron-oxide, illite, kaolinite and pyrite cements; dissolution of feldspars, rock fragments. Silica dissolution, grain replacement and carbonate dissolution greatly enhance the petrophysical properties of many sandstone samples.

Petrographic and chemical reconnaissance study of some granitic and gneissic rocks near the San Andreas fault from Bodega Head to Cajon Pass, California

USGS Publications Warehouse

Ross, Donald C.

1972-01-01

This petrographic and chemical study is based on reconnaissance sampling of granitic and related gneissic rock in the California Coast and Transverse Ranges. In the Coast Ranges, granitic rocks are restricted to an elongate belt, the Salinian block, between the San Andreas and Sur-Nacimiento fault zones. These rocks have a considerable compositional range, but are dominantly quartz monzonite and granodiorite. Moist of the Salinian block seems to be a structurally coherent basement block of chemically related granitic rocks. However, on both the east and the west sides of the block, gneiss crops out in abundance; these rocks may be structurally separate from the main part of the Salinian block. In the Transverse Ranges, the granitic and related rocks are dominantly of granodiorite composition, and in many areas granitic and gneissic rocks are intimately intermixed.Chemically the rocks of the California Coast and Transverse Ranges are somewhat intermediate in character between those of the east-central part of the Sierra Nevada batholith and those of the western part of the Sierra Nevada batholith and the southern California batholith. Probably the closest similarity is to the east-central Sierra Nevada rocks, but the rocks of the Coast and Transverse Ranges are somewhat higher in Al2O3 and lower in K2O than Sierran rocks of the comparable SiO2 content.Granitic basement rocks of the Salinian block are now anomalously sandwiched between Franciscan terranes. The petrographic and chemical data are compatible with the concept that the Salinian rocks were originally part of the great batholithic belt along the west coast, which is exemplified by the Sierra Nevada hatholith. It also seems most likely that the Salinian block was transported from somewhere south of the Sierra Nevada batholith by large-scale right-lateral movement along the San Andreas fault zone.

Jurassic rifting at the Eurasian Tethys margin: Geochemical and geochronological constraints from granitoids of North Makran, southeastern Iran

NASA Astrophysics Data System (ADS)

Hunziker, Daniela; Burg, Jean-Pierre; Bouilhol, Pierre; von Quadt, Albrecht

2015-03-01

This study focuses on an east-west trending belt of granitic to intermediate intrusions and their volcanic cover in the northern Dur Kan Complex, a continental slice outcropping to the north of the exposed Makran accretionary wedge in southeastern Iran. Field observations, petrographic descriptions, trace element, and isotope analyses combined with U-Pb zircon geochronology are presented to determine the time frame of magmatism and tectonic setting during the formation of these rocks. Results document three magmatic episodes with different melt sources for (1) granites, (2) a diorite-trondhjemite-plagiogranite sequence, and (3) diabases and lavas. Granites, dated at 170-175 Ma, represent crystallized melt with a strong continental isotopic contribution. The diorite-trondhjemite-plagiogranite sequence is 165-153 Ma old and derives from a mantle magma source with minor continental contribution. East-west trending diabase dikes and bodies intruded the granitoids, which were eroded and then covered by Valanginian (140-133 Ma) alkaline lavas and sediments. Alkaline dikes and lavas have a mantle isotopic composition. Temporal correlation with plutonites of the Sanandaj-Sirjan Zone to the northwest defines a narrow, NW-SE striking and nearly 2000 km long belt of Jurassic intrusions. The increasing mantle influence in the magma sources is explained by thinning of continental lithosphere and related mantle upwelling/decompression melting. Accordingly, the formation of the studied igneous rocks is related to the extension of the Iranian continental margin, which ultimately led to the formation of the Tethys-related North Makran Ophiolites.

Ferromanganese deposits from the Gulf of Alaska seamount province: mineralogy, chemistry, and origin.

USGS Publications Warehouse

Koski, R.A.

1988-01-01

Petrographic and chemical data presented and discussed permit the following conclusions regarding the high-latitude Gulf of Alaska (GA) Fe-Mn deposits: 1) thick (10-50 mm) Fe-Mn crusts form on alkali-basalt and volcaniclastic substrates by hydrogenetic processes, contain delta -MnO2 as the principal Mn phase, and have compositions similar to those of seamount crusts from comparable depths in the Hawaiian archipelago. GA crusts have higher Mn/Fe and lower Co contents than crusts from low-altitude, central Pacific seamounts; 2) thin (<10 mm) crusts on tuffaceous conglomerate, sandstone and phosphorite have a high proportion of crystalline Mn oxides and are genetically related to vein deposits; 3) vein deposits of todorokite and cryptomelane form during low-T oxidative diagenesis of volcanogenic sediment. Mn and other transition metals are supplied during the initial palagonitization of basaltic glass. The oxidation of Fe2+ to Fe3+ in palagonite and the dissolution of the diluted microfossil fraction of the sediment lower the Eh of the ambient pore fluid and enhance the solubility of Mn2+. The K released during the formation of palagonite may be redeposited in secondary phyllosilicate minerals, phillipsite, todorokite and cryptomelane; 4) the vein deposits formed soon after the deposition of sediment derived from the erosion and mass wasting of Mill Seamount but before crust deposition. Therefore, the deposition of hydrogenous crusts and the deposition of diagenetic veins are chemically distinct processes in time and space.-J.M.H.

Stratigraphic and facies analysis of Ste. Genevieve Limestone, Putnam County, Indiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stevenson, G.M.

1987-05-01

The Ste. Genevieve Limestone (Mississippian) in Putnam County, Indiana, was deposited on a southwestward-sloping ramp in the northeastern portion of the Illinois basin. This portion of the Ste. Genevieve Limestone is divided into three members which, in ascending order, are the Fredonia, the Spar Mountain, and the Levias. The Fredonia Member appears to be homogeneous biomicrite on out-crop, but petrographic analysis reveals mottling and distinguishable pellets and is classified as pelbiosparite. Storm deposits are observed and typically are composed of fossil hash zones (biopelsparite) overlain by calcitic shale layers. Bioclasts consist of stenohaline forms with foraminifera, echinoderms, and bryozoans predominant.more » The gray-green shale layers represent punctuated terrigenous influx in this shallow restricted shelf. The Spar Mountain Member is commonly cross-bedded calcarenite but commonly lacks the quartz and is oolitic-pelbiosparite. The dominant particle types are quartz-centered ooids, peloids, and echinoderm fragments. Relatively high energy conditions and herringbone-cross-beds suggest deposition of a shoal with tidal current influence. The Levias Member is thin-bedded biopelsparite which represents shallow shelf deposition. The Bryantsville Breccia Bed varies in thickness across the study area and marks the top of the Levias Member. Oolitic-biopelsparite centimeter-sized clasts are contained in a matrix of similar material, suggesting an intraformational mode of origin, possibly a collapse breccia. Two incomplete shoaling-upward cycles are present in this Ste. Genevieve sequence. The lower portion of each cycle is pelbiosparite/biopelsparite overlain by oolitic-pelbiosparite and/or calcarenite.« less

Depositional environments of the uranium-bearing Cutler Formations, Lisbon Valley, Utah

USGS Publications Warehouse

Campbell, John A.; Steele-Mallory, Brenda A.

1979-01-01

The Cutler Formation in Lisbon Valley, San Juan County, Utah, is composed predominantly of fluvial arkosic sandstones, siltstones, shales, and mudstones that were deposited by meandering streams that flowed across a flood plain and tidal flat close to sea level. Two types of channel deposits are recognized from their sedimentary structures: meandering and distributary. The flood plain was occasionally transgressed by a shallow sea from the west, resulting in the deposition of several thin limestones and marine sandstones. The marine sandstones were deposited as longshore bars. Wind transported sand along the shoreline of the shallow sea, forming a coastal dune field. Marine sandstones and eolian sandstones are more common in the upper Cutler in the southern part of the area, whereas in the central and northern part of the area the formation is predominantly fluvial. Crossbed orientation indicates that Cutler streams flowed S. 67? W. on the the average, whereas marine currents moved sediment S. 36? E. and N. 24? W., and wind transported sand S. 800 E. The uranium in the Cutler is found in the central and northern part of the area, in the upper part of the formation, in small fluvial sandstone bodies that were deposited predominantly in a distributary environment. No uranium is known in the marine or eolian sandstones. Petrographically, the uranium-bearing sandstones are identical to other Cutler fluvial sandstones except that they contain less calcite and more clay and are slightly coarser grained. Ore formation has modified the host sandstones very little.

Application of SAXS and SANS in evaluation of porosity, pore size distribution and surface area of coal

USGS Publications Warehouse

Radlinski, A.P.; Mastalerz, Maria; Hinde, A.L.; Hainbuchner, M.; Rauch, H.; Baron, M.; Lin, J.S.; Fan, L.; Thiyagarajan, P.

2004-01-01

This paper discusses the applicability of small angle X-ray scattering (SAXS) and small angle neutron scattering (SANS) techniques for determining the porosity, pore size distribution and internal specific surface area in coals. The method is noninvasive, fast, inexpensive and does not require complex sample preparation. It uses coal grains of about 0.8 mm size mounted in standard pellets as used for petrographic studies. Assuming spherical pore geometry, the scattering data are converted into the pore size distribution in the size range 1 nm (10 A??) to 20 ??m (200,000 A??) in diameter, accounting for both open and closed pores. FTIR as well as SAXS and SANS data for seven samples of oriented whole coals and corresponding pellets with vitrinite reflectance (Ro) values in the range 0.55% to 5.15% are presented and analyzed. Our results demonstrate that pellets adequately represent the average microstructure of coal samples. The scattering data have been used to calculate the maximum surface area available for methane adsorption. Total porosity as percentage of sample volume is calculated and compared with worldwide trends. By demonstrating the applicability of SAXS and SANS techniques to determine the porosity, pore size distribution and surface area in coals, we provide a new and efficient tool, which can be used for any type of coal sample, from a thin slice to a representative sample of a thick seam. ?? 2004 Elsevier B.V. All rights reserved.

Diagenesis of an 'overmature' gas reservoir: The Spiro sand of the Arkoma Basin, USA

USGS Publications Warehouse

Spotl, C.; Houseknecht, D.W.; Burns, S.J.

1996-01-01

The Spiro sand is a laterally extensive thin sandstone of earliest Atokan (Pennsylvanian) age that forms a major natural gas reservoir in the western Arkoma Basin, Oklahoma. Petrographic analysis reveals a variety of diagenetic alterations, the majority of which occurred during moderate to deep burial. Early diagenetic processes include calcite cementation and the formation of Fe-clay mineral peloids and coatings around quartz framework grains. These clays, which underwent transformation to well-crystallized chamosite [polytype Ib(?? = 90??)] on burial, are particularly abundant in medium-grained channel sandstones, whereas illitic clays are predominant in fine-grained interchannel sandstones. Subsequent to mechanical compaction, saddle ankerite precipitated in the reservoir at temperatures in excess of 70??C. Crude oil collected in favourable structural locations during and after ankeritization. Whereas hydrocarbons apparently halted inorganic diagenesis in oil-saturated zones, cementation continued in the underlying water-saturated zones. As reservoir temperatures increased further, hydrocarbons were cracked and a solid pyrobitumen residue remained in the reservoir. At temperatures exceeding ???140-150??C, non-syntaxial quartz cement, ferroan calcite and traces of dickite(?) locally reduced the reservoir quality. Local secondary porosity was created by carbonate cement dissolution. This alteration post-dated hydrocarbon emplacement and is probably related to late-stage infiltration of freshwater along 'leaky' faults. The study shows that the Spiro sandstone locally retained excellent porosities despite deep burial and thermal conditions that correspond to the zone of incipient very low grade metamorphism.

Analytical SuperSTEM for extraterrestrial materials research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bradley, J P; Dai, Z R

2009-09-08

Electron-beam studies of extraterrestrial materials with significantly improved spatial resolution, energy resolution and sensitivity are enabled using a 300 keV SuperSTEM scanning transmission electron microscope with a monochromator and two spherical aberration correctors. The improved technical capabilities enable analyses previously not possible. Mineral structures can be directly imaged and analyzed with single-atomic-column resolution, liquids and implanted gases can be detected, and UV-VIS optical properties can be measured. Detection limits for minor/trace elements in thin (<100 nm thick) specimens are improved such that quantitative measurements of some extend to the sub-500 ppm level. Electron energy-loss spectroscopy (EELS) can be carried outmore » with 0.10-0.20 eV energy resolution and atomic-scale spatial resolution such that variations in oxidation state from one atomic column to another can be detected. Petrographic mapping is extended down to the atomic scale using energy-dispersive x-ray spectroscopy (EDS) and energy-filtered transmission electron microscopy (EFTEM) imaging. Technical capabilities and examples of the applications of SuperSTEM to extraterrestrial materials are presented, including the UV spectral properties and organic carbon K-edge fine structure of carbonaceous matter in interplanetary dust particles (IDPs), x-ray elemental maps showing the nanometer-scale distribution of carbon within GEMS (glass with embedded metal and sulfides), the first detection and quantification of trace Ti in GEMS using EDS, and detection of molecular H{sub 2}O in vesicles and implanted H{sub 2} and He in irradiated mineral and glass grains.« less

Plume-Ridge Interaction on the Cocos Plate (ODP Leg 205, Costa Rica): Implication for Fluid Circulation

NASA Astrophysics Data System (ADS)

Dreyer, B.; Chavagnac, V.; Font, L.; Morris, J.; Schramm, B.; Chavagnac, V.; Font, L.; Schramm, B.; Dreyer, B.; Morris, J. D.

2004-12-01

At subduction zone, the permeability and hydrology of the down-going igneous section play a key role on the behaviour of the seismogenic zone, which produces earthquake and tsunamis. We present, here, evidence of fluid circulation pathways in the igneous section being subducted at the Central American convergent margin (Site 1253 ODP Leg 205, Costa Rica). The geological evolution of the Cocos plate over the last 25 Ma is complicated as a result of plate boundaries re-arrangement (Silver et al., 1998). The Cocos-Nazca spreading centre (CNS) interacted with the Galapagos hotspot, which simultaneously deposited volcanic material on both side of the CNS, on the Cocos and Nazca plates. The oceanic crust of the Cocos and Nazca plates was formed along four spreading centres (Meschede et al., 1998) and the East Pacific Rise (EPR). The EPR oceanic crust has the featureless morphology and low-amplitude magnetic anomalies common to fast spreading ridge (Wilson & Hey, 1995) while the CNS oceanic crust presents a rough topography and high-amplitude magnetic anomalies (Wilson & Hey, 1995). We wish to focus on the ODP 1253 Site drilled in the Cocos plate because it samples the igneous input (rock, heat and fluid) to the Central American subduction zone. Coring at Site 1253 penetrated two separate igneous Units of which the upper one is a sill (Unit 4A) separated from the lower Unit (Unit 4B) by sediment. Both Unit 4A and 4B present similar texture, structure and mineralogy apart from the thin basaltic interval at 513 mbsf, below which Unit 4B becomes more glass-rich and altered. Unit 4B is either a sill complex with multiple intrusions related to the Galapagos volcanic activity or a series of thick slowly cooled lava flows formed at the EPR. Some of these characteristics of Unit 4B are similar to those seen in horizons recovered at Site 1256, which intersected thick-ponded lava flows. Analyses of marine magnetic anomalies indicate that the crust at Site 1253 was formed at EPR 25 Ma ago. However, its thermal gradients and conductivity yield surface heat flow anomalies of 10-40 mWm2, which is ˜70% lower than normal cooling lithosphere of that age (Fisher et al., 2003). Off-axis magmatic and tectonic activity associated with the formation of the Cocos Ridge may have increased fluid circulation pathways within the basement structure. Mobile trace element (Ba, Sr) and Sr isotope variations in conjunction with petrographic observation help identify horizons of fluid/rock interaction, e.g. fluid circulation pathways within Unit 4A and 4B. Based on veins, fractures, and void occurrences, the Unit 4A and 4B were subdivided into two and seven subunits respectively. Along the core-depth profile, mobile element concentrations and 87Sr/86Sr ratios vary mainly in a narrow range (0.703245 and 0.703503) but are still higher than those of EPR or the Galapagos hotspot (<0.703). At sub-unit interface, we observe drastic increases in Ba and Sr content and more radiogenic Sr isotope signature (up to 0.705106), especially above the thin basaltic horizon. This reflects exchange of Sr with seawater or hydrothermal fluids during alteration. Further work will determine fluid flux estimate at Site 1253. The origin, nature and structure of the oceanic crust at Site 1253 will be presented in two additional abstracts (see Dreyer and Moe, this session).

LA-ICP-MS Study of Trace Elements in the Chanuskij Metal

NASA Technical Reports Server (NTRS)

Petaev, Michail I.

2005-01-01

This progress report covers work done during the second year of the 3-year proposal. During this year we resolved many issues relevant to the analytical technique developed by us for measuring trace elements in meteoritic metals. This technique was used to measure concentrations of Fe, Ni, Co, Cr, Cu, Ga, Ge, As, Mo, Ru, Rh, Pd, Sb, W, Re, Os, Ir, Pt, and Au in eight large (120 - 160 microns) metal grains from both "igneous" and "metamorphic" lithologies of the Chanuskij silicate inclusions. The first application of OUT technique to metal grains from thin sections showed some limitations. Small thickness of metal grains in the thin section limited the signal to 3-4 time-slices instead of 10- 1 1 ones in polished sections of iron meteorites studied before.

Improving FTIR imaging speciation of organic compound residues or their degradation products in wall painting samples, by introducing a new thin section preparation strategy based on cyclododecane pre-treatment.

PubMed

Papliaka, Zoi Eirini; Vaccari, Lisa; Zanini, Franco; Sotiropoulou, Sophia

2015-07-01

Fourier transform infrared (FTIR) imaging in transmission mode, employing a bidimensional focal plane array (FPA) detector, was applied for the detection and spatially resolved chemical characterisation of organic compounds or their degradation products within the stratigraphy of a critical group of fragments, originating from prehistoric and roman wall paintings, containing a very low concentration of subsisted organic matter or its alteration products. Past analyses using attenuated total reflection (ATR) or reflection FTIR on polished cross sections failed to provide any evidence of any organic material assignable as binding medium of the original painting. In order to improve the method's performance, in the present study, a new method of sample preparation in thin section was developed. The procedure is based on the use of cyclododecane C12H24 as embedding material and a subsequent double-side polishing of the specimen. Such procedure provides samples to be studied in FTIR transmission mode without losing the information on the spatial distribution of the detected materials in the paint stratigraphy. For comparison purposes, the same samples were also studied after opening their stratigraphy with a diamond anvil cell. Both preparation techniques offered high-quality chemical imaging of the decay products of an organic substance, giving clues to the painting technique. In addition, the thin sections resulting from the cyclododecane pre-treatment offered more layer-specific data, as the layer thickness and order remained unaffected, whereas the samples resulting from compression within the diamond cell were slightly deformed; however, since thinner and more homogenous, they provided higher spectral quality in terms of S/N ratio. In summary, the present study illustrates the appropriateness of FTIR imaging in transmission mode associated with a new thin section preparation strategy to detect and localise very low-concentrated organic matter subjected to deterioration processes, when the application of FTIR in reflection mode or FTIR-ATR fails to give any relevant information.

A Computer Program which Uses an Expert Systems Approach to Identifying Minerals.

ERIC Educational Resources Information Center

Hart, Allan Bruce; And Others

1988-01-01

Described is a mineral identification program which uses a shell system for creating expert systems of a classification nature. Discusses identification of minerals in hand specimens, thin sections, and polished sections of rocks. (Author/CW)

Thermal runaway and microwave heating in thin cylindrical domains

NASA Astrophysics Data System (ADS)

Ward, Michael J.

2002-04-01

The behaviour of the solution to two nonlinear heating problems in a thin cylinder of revolution of variable cross-sectional area is analysed using asymptotic and numerical methods. The first problem is to calculate the fold point, corresponding to the onset of thermal runaway, for a steady-state nonlinear elliptic equation that arises in combustion theory. In the limit of thin cylindrical domains, it is shown that the onset of thermal runaway can be delayed when a circular cylindrical domain is perturbed into a dumbell shape. Numerical values for the fold point for different domain shapes are obtained asymptotically and numerically. The second problem that is analysed is a nonlinear parabolic equation modelling the microwave heating of a ceramic cylinder by a known electric field. The basic model in a thin circular cylindrical domain was analysed in Booty & Kriegsmann (Meth. Appl. Anal. 4 (1994) p. 403). Their analysis is extended to treat thin cylindrical domains of variable cross-section. It is shown that the steady-state and dynamic behaviours of localized regions of high temperature, called hot-spots, depend on a competition between the maxima of the electric field and the maximum deformation of the circular cylinder. For a dumbell-shaped region it is shown that two disconnected hot-spot regions can occur. Depending on the parameters in the model, these regions, ultimately, either merge as time increases or else remain as disconnected regions for all time.

Nanoskiving: A new method for nanofabrication

NASA Astrophysics Data System (ADS)

Xu, Qiaobing

"Nanoskiving" is the name we have given to a technique for the fabrication of nanostructures by combining deposition of thin films on a topographically patterned polymeric substrate using physical vapor methods and sectioning with an ultramicrotome. Ultramicrotomy was originally developed as a tool for sectioning biological specimens for analysis by optical or electron microscopy. The imaging of biological specimens requires the ability to slice mum to sub-mum thick sections and the imaging is done through the thinnest dimension of the section. Nanoskiving utilizes an ultramicrotome because of its ability to section sub-100 nm slices reproducibly. In this thesis, I will describe the fabrication by nanoskiving of the diverse nanostructures and their applications in electronics and optics. Nanoskiving is experimentally simple, and requires little in the way of facilities (for example, access to a cleanroom or a high-resolution e-beam writer is unnecessary). It is applicable to many classes of structures and materials with which conventional methods of nanofabrication (e.g. EUV or X-ray photolithography, e-beam lithography (EBL) focused ion-beam (FIB)) fail. This method begins with the deposition of thin metallic films on an epoxy substrate by e-beam evaporation or sputtering. After embedding the thin metallic film in an epoxy matrix, sectioning (in a plane perpendicular or parallel to the metal film) with an ultramicrotome generates nanometer-thick sections of epoxy containing metallic nanostructures. The cross-section of the metal wires embedded in the resulting thin epoxy sections is controlled by the thickness of the evaporated metal film (which can be as small as 20 nm), and the thickness of the sections cut by the microtome (as small as 30 nm, using a standard 35° diamond knife). The embedded nanostructures can be transferred to, and positioned on planar or curved substrates by manipulating the thin polymer film. Removal of the epoxy matrix by etching with an oxygen plasma generates free-standing metallic nanostructures. Chapter 1 is an overview of nanoskiving---a technique that combines thin-film deposition of metal on a topographically contoured substrate with sectioning using an ultramicrotome---as a method of fabricating nanostructures. Nanoskiving provides a simple and convenient procedure to produce arrays (over areas of mm2 to cm2) of structures with cross-sectional dimensions in the thirty-nanometer regime embedded in epoxy. The ability to control the dimensions of nanostructures, combined with the ability to manipulate and position them, enables the fabrication of nanostructures with geometries that are difficult to prepare by other methods. Two classes of applications--- in optics and in electronics---demonstrate the utility of nanostructures fabricated by nanoskiving. Chapter 2 shows the fabrication by nanoskiving of complex nanostructures that are difficult or impossible to achieve by other nanofabrication methods. These include multilayer structures, structures on curved surfaces, structures that span gaps, structures in less familiar materials, structures with high-aspect ratios, and large-area structures comprising two-dimensional periodic arrays. Chapter 3 demonstrates the Fabrication patterned arrays of gold structures (for example, rings) with wall thickness of 40 nm, and with high aspect ratios up to 25. Chapter 4 introduces the fabrication by nanoskiving of gold nanowires of uniform, controllable length, width, and height, and describes a systematic study of the dependence of the surface plasmon resonance on the geometry of these wires. Chapter 5 describes the fabrication of arrays of closed and open, loop-shaped nanostructures over mm2 area by nanoskiving. These arrays of metallic structures serve as frequency-selective surfaces at mid-infrared wavelengths. Chapter 6 describes a procedure to fabricate an array of nanoelectrodes that can be addressed from the back face of the slab of epoxy resin.

Thin Film Ceramic Strain Sensor Development for Harsh Environments: Interim Report on Identification of Candidate Thin Film Ceramics to Test for Viability for Static Strain Sensor Development

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Fralick, Gustave C.; Hunter, Gary W.

2006-01-01

The need to consider ceramic sensing elements is brought about by the temperature limits of metal thin film sensors in propulsion system applications. In order to have a more passive method of negating changes of resistance due to temperature, an effort is underway at NASA Glenn to develop high temperature thin film ceramic static strain gauges for application in turbine engines, specifically in the fan and compressor modules on blades. Other applications can be on aircraft hot section structures and on thermal protection systems. The near-term interim goal of the research effort was to identify candidate thin film ceramic sensor materials to test for viability and provide a list of possible thin film ceramic sensor materials and corresponding properties to test for viability. This goal was achieved by a thorough literature search for ceramics that have the potential for application as high temperature thin film strain gauges, reviewing potential candidate materials for chemical and physical compatibility with our microfabrication procedures and substrates.

Thin Film Ceramic Strain Sensor Development for Harsh Environments: Identification of Candidate Thin Film Ceramics to Test for Viability for Static Strain Sensor Development

NASA Technical Reports Server (NTRS)

Wrbanek, John D.; Fralick, Gustave C.; Hunter, Gary W.

2006-01-01

The need to consider ceramic sensing elements is brought about by the temperature limits of metal thin film sensors in propulsion system applications. In order to have a more passive method of negating changes of resistance due to temperature, an effort is underway at NASA GRC to develop high temperature thin film ceramic static strain gauges for application in turbine engines, specifically in the fan and compressor modules on blades. Other applications include on aircraft hot section structures and on thermal protection systems. The near-term interim goal of this research effort was to identify candidate thin film ceramic sensor materials to test for viability and provide a list of possible thin film ceramic sensor materials and corresponding properties to test for viability. This goal was achieved by a thorough literature search for ceramics that have the potential for application as high temperature thin film strain gauges, reviewing potential candidate materials for chemical & physical compatibility with NASA GRC's microfabrication procedures and substrates.

Microstructural investigation of nickel silicide thin films and the silicide-silicon interface using transmission electron microscopy.

PubMed

Bhaskaran, M; Sriram, S; Mitchell, D R G; Short, K T; Holland, A S; Mitchell, A

2009-01-01

This article discusses the results of transmission electron microscopy (TEM)-based investigation of nickel silicide (NiSi) thin films grown on silicon. Nickel silicide is currently used as the CMOS technology standard for local interconnects and in electrical contacts. Films were characterized with a range of TEM-based techniques along with glancing angle X-ray diffraction. The nickel silicide thin films were formed by vacuum annealing thin films of nickel (50 nm) deposited on (100) silicon. The cross-sectional samples indicated a final silicide thickness of about 110 nm. This investigation studied and reports on three aspects of the thermally formed thin films: the uniformity in composition of the film using jump ratio maps; the nature of the interface using high resolution imaging; and the crystalline orientation of the thin films using selected-area electron diffraction (SAED). The analysis highlighted uniform composition in the thin films, which was also substantiated by spectroscopy techniques; an interface exhibiting the desired abrupt transition from silicide to silicon; and desired and preferential crystalline orientation corresponding to stoichiometric NiSi, supported by glancing angle X-ray diffraction results.

Elastica solution for a nanotube formed by self-adhesion of a folded thin film

NASA Astrophysics Data System (ADS)

Glassmaker, N. J.; Hui, C. Y.

2004-09-01

Schmidt and Eberl demonstrated the construction of tubes with submicron diameters by the method of folding thin solid films [Nature (London) 410, 168 (2001)]. In their method, a thin film is folded 180° and brought into adhesive contact with itself. The resulting sealed loop forms a nanotube with the thickness of the tube walls equal to the thickness of the thin film. The calculation of the diameter of the tube and the shape of its cross section in equilibrium are the subjects of this study. The tube is modeled as a two-dimensional elastica when viewed in cross section, and adhesive behavior is governed by an energy release rate criterion. A numerical technique is used to find elastic equilibria for a large range of material parameters. With these solutions in hand, the problem of designing a nanotube becomes transparent. It is shown that one dimensionless parameter determines the diameter of the nanotube, while another fixes its shape. Each of these parameters is a ratio involving the material's mechanical properties and the film thickness. Before concluding, we verify our model by comparing its results with the experimental observations of Schmidt and Eberl, for their materials.

Berkovich Nanoindentation on AlN Thin Films.

PubMed

Jian, Sheng-Rui; Chen, Guo-Ju; Lin, Ting-Chun

2010-03-31

Berkovich nanoindentation-induced mechanical deformation mechanisms of AlN thin films have been investigated by using atomic force microscopy (AFM) and cross-sectional transmission electron microscopy (XTEM) techniques. AlN thin films are deposited on the metal-organic chemical-vapor deposition (MOCVD) derived Si-doped (2 × 1017 cm-3) GaN template by using the helicon sputtering system. The XTEM samples were prepared by means of focused ion beam (FIB) milling to accurately position the cross-section of the nanoindented area. The hardness and Young's modulus of AlN thin films were measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) option. The obtained values of the hardness and Young's modulus are 22 and 332 GPa, respectively. The XTEM images taken in the vicinity regions just underneath the indenter tip revealed that the multiple "pop-ins" observed in the load-displacement curve during loading are due primarily to the activities of dislocation nucleation and propagation. The absence of discontinuities in the unloading segments of load-displacement curve suggests that no pressure-induced phase transition was involved. Results obtained in this study may also have technological implications for estimating possible mechanical damages induced by the fabrication processes of making the AlN-based devices.

Structural and optical properties of cobalt doped multiferroics BiFeO3 nanostructure thin films

NASA Astrophysics Data System (ADS)

Prasannakumara, R.; Naik, K. Gopalakrishna

2018-05-01

Bismuth ferrite (BiFeO3) and Cobalt doped BiFeO3 (BiFe1-XCoXO3) nanostructure thin films were deposited on glass substrates by the sol-gel spin coating method. The X-ray diffraction patterns (XRD) of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films showed distorted rhombohedral structure. The shifting of peaks to higher angles was observed in cobalt doped BiFeO3. The surface morphology of the BiFeO3 and BiFe1-XCoXO3 nanostructure thin films were studied using FESEM, an increase in grain size was observed as Co concentration increases. The thickness of the nanostructure thin films was examined using FESEM cross-section. The EDX studies confirmed the elemental composition of the grown BiFeO3 and BiFe1-XCoXO3 nanostructure thin films. The optical characterizations of the grown nanostructure thin films were carried out using FTIR, it confirms the existence of Fe-O and Bi-O bands and UV-Visible spectroscopy shows the increase in optical band gap of the BiFeO3 nanostructure thin films with Co doping by ploting Tauc plot.

Measurement of the differential cross sections of 6Li(d,d0) for Ion Beam Analysis purposes

NASA Astrophysics Data System (ADS)

Ntemou, E.; Aslanoglou, X.; Axiotis, M.; Foteinou, V.; Kokkoris, M.; Lagoyannis, A.; Misaelides, P.; Patronis, N.; Preketes-Sigalas, K.; Provatas, G.; Vlastou, R.

2017-09-01

In the present work, the 6Li(d,d0)6Li elastic scattering differential cross sections were measured in the energy range Ed,lab = 940-2000 keV for Elastic Backscattering Spectroscopy (EBS) purposes, using thin lithium targets, made by evaporating isotopically enriched 6LiF powder on self-supporting carbon foils, with an ultra-thin Au layer on top for normalization purposes. The experiment was carried out in deuteron beam energy steps of 20 or 30 keV and for the laboratory scattering angles of 125°, 140°, 150°, 160°, and 170°.

Immunoelectron microscopic double labeling of alkaline phosphatase and penicillinase with colloidal gold in frozen thin sections of Bacillus licheniformis 749/C.

PubMed Central

Guan, T; Ghosh, A; Ghosh, B K

1985-01-01

The subcellular distribution of alkaline phosphatase and penicillinase was determined by double labeling frozen thin sections of Bacillus licheniformis 749/C with colloidal gold-immunoglobulin G (IgG). Antipenicillinase and anti-alkaline phosphatase antibodies were used to prepare complexes with 5- and 15-nm colloidal gold particles, respectively. The character of the labeling of membrane-bound alkaline phosphatase and penicillinase was different: the immunolabels for alkaline phosphatase (15-nm particles) were bound to a few sites at the inner surface of the plasma membrane, and the gold particles formed clusters of various sizes at the binding sites; the immunolabels for penicillinase (5-nm particles), on the other hand, were bound to the plasma membrane in a dispersed and random fashion. In the cytoplasm, immunolabels for both proteins were distributed randomly, and the character of their binding was similar. The labeling was specific: pretreating the frozen thin sections with different concentrations of anti-alkaline phosphatase or penicillinase blocked the binding of the immunolabel prepared with the same antibody. Binding could be fully blocked by pretreatment with 800 micrograms of either antibody per ml. Images PMID:3876329

ToF-SIMS cluster ion imaging of hippocampal CA1 pyramidal rat neurons

NASA Astrophysics Data System (ADS)

Francis, J. T.; Nie, H.-Y.; Taylor, A. R.; Walzak, M. J.; Chang, W. H.; MacFabe, D. F.; Lau, W. M.

2008-12-01

Recent studies have demonstrated the power of time-of-flight secondary ion mass spectrometry (ToF-SIMS) cluster ion imaging to characterize biological structures, such as that of the rat central nervous system. A large number of the studies to date have been carried out on the "structural scale" imaging several mm 2 using mounted thin sections. In this work, we present our ToF-SIMS cluster ion imaging results on hippocampal rat brain neurons, at the cellular and sub-cellular levels. As a part of an ongoing investigation to examine gut linked metabolic factors in autism spectrum disorders using a novel rat model, we have observed a possible variation in hippocampal Cornu ammonis 1 (CA1) pyramidal neuron geometry in thin, paraformaldehyde fixed brain sections. However, the fixation process alters the tissue matrix such that much biochemical information appears to be lost. In an effort to preserve as much as possible this original information, we have established a protocol using unfixed thin brain sections, along with low dose, 500 eV Cs + pre-sputtering that allows imaging down to the sub-cellular scale with minimal sample preparation.

Reconstruction of three-dimensional porous media using a single thin section

NASA Astrophysics Data System (ADS)

Tahmasebi, Pejman; Sahimi, Muhammad

2012-06-01

The purpose of any reconstruction method is to generate realizations of two- or multiphase disordered media that honor limited data for them, with the hope that the realizations provide accurate predictions for those properties of the media for which there are no data available, or their measurement is difficult. An important example of such stochastic systems is porous media for which the reconstruction technique must accurately represent their morphology—the connectivity and geometry—as well as their flow and transport properties. Many of the current reconstruction methods are based on low-order statistical descriptors that fail to provide accurate information on the properties of heterogeneous porous media. On the other hand, due to the availability of high resolution two-dimensional (2D) images of thin sections of a porous medium, and at the same time, the high cost, computational difficulties, and even unavailability of complete 3D images, the problem of reconstructing porous media from 2D thin sections remains an outstanding unsolved problem. We present a method based on multiple-point statistics in which a single 2D thin section of a porous medium, represented by a digitized image, is used to reconstruct the 3D porous medium to which the thin section belongs. The method utilizes a 1D raster path for inspecting the digitized image, and combines it with a cross-correlation function, a grid splitting technique for deciding the resolution of the computational grid used in the reconstruction, and the Shannon entropy as a measure of the heterogeneity of the porous sample, in order to reconstruct the 3D medium. It also utilizes an adaptive technique for identifying the locations and optimal number of hard (quantitative) data points that one can use in the reconstruction process. The method is tested on high resolution images for Berea sandstone and a carbonate rock sample, and the results are compared with the data. To make the comparison quantitative, two sets of statistical tests consisting of the autocorrelation function, histogram matching of the local coordination numbers, the pore and throat size distributions, multiple-points connectivity, and single- and two-phase flow permeabilities are used. The comparison indicates that the proposed method reproduces the long-range connectivity of the porous media, with the computed properties being in good agreement with the data for both porous samples. The computational efficiency of the method is also demonstrated.

Palynologic and petrographic intervals in the upper Pennsylvanian McLeansboro Group, Western Kentucky

USGS Publications Warehouse

Hower, J.C.; Helfrich, C.T.; Williams, D.A.

1994-01-01

The McLeansboro Group (formerly the Sturgis Formation) in the Western Kentucky coal field spans the upper Desmoinesian (Westphalian D) and the Missourian and Virgilian series (Stephanian). Extensive drilling has demonstrated the lateral continuity of major and minor beds in the group, making it possible to study vertical and lateral changes in palynology and petrology. Significant features of the McLeansboro Group are the marine zones over most of the coals and paleochannels, which are the only disruptions to the continuity of other lithologies. The Desmoinesian Baker (No. 13) and Wheatcroft (No. 13a) coal beds were included in the study but the primary emphasis is on the Missourian and Virgilian coals. Patoka Formation (lower Missourian) coals are dominated by tree fern spores with lesser amounts of sphenopsids, ferns and cordaites spores. This is in marked contrast to the arborescent lycopod-dominated Desmoinesian coals. Only the No. 15 coal bed exceeds 80% vitrinite: the vitrinite content of the No. 16 coal bed is less than 72%, the lowest of any Western Kentucky humic coal. The Bond Formation (upper Missourian) represents a distinct floristic interval, with a greater diversity of plant groups than in the Patoka Formation. Herbaceous lycopod spores, which are relatively minor contributors to the Patoka coals, are common in the Bond Formation. The coals generally exceed 80% vitrinite. The Mattoon Formation (Virgillian) coals have a variety of palynomorph assemblages. The low-sulfur Geiger Lake coal bed is dominated by tree fern spores, with important contributions from other ferns and sphenopsids. Similar to the underlying tree fern interval, vitrinite contents are less than 80%. The uppermost Mattoon coals are dominated by tree ferns and are notable in being the only coals more than 1 m thick in the Stephanian portion of the section, with the top coal being 4.3 m thick. The uppermost coals generally contain more than 80% vitrinite. The Permian Mauzy Formation overlies the McLeansboro Group. The palynologic/petrographic intervals appear to represent fluctuating dry (low vitrinite) and wet intervals within the Stephanian, which was itself drier than the Westphalian D. ?? 1994.

Research notes : studded tire damage repair : the first year.

DOT National Transportation Integrated Search

1998-02-01

The Oregon Department of Transportation has monitored rutting caused by studded tires since 1974. In the past decade, the damage has increased rapidly. The overlay was divided into four sections. Each section received a different type of thin asphalt...

Forensic Investigation of AC and PCC Pavements with Extended Service Life : Volume 2 : Petrographic Examination of PCC Core Samples at Lankard Materials Laboratory ; Executive Summary Report

DOT National Transportation Integrated Search

2010-09-01

The overall purpose of this research project as described in : the Executive Summary Report for Volume 1 : (FHWA/OH-2010/04A) is to identify flexible, rigid and : composite pavements that have not received any structural : maintenance since construct...

Sedimentation and tectonics of the Sylhet trough, Bangladesh

USGS Publications Warehouse

Johnson, S.Y.; Nur Alam, A.M.

1991-01-01

The Sylhet trough, a sub-basin of the Bengal Basin in northeastern Bangladesh, contains a thick fill (12 to 16 km) of late Mesozoic and Cenozoic strata that record its tectonic evolution. Stratigraphic, sedimentologic, and petrographic data collected from outcrops, cores, well logs, and seismic lines are used to reconstruct the history of this trough. -from Authors

National Register Testing of 42 Prehistoric Archeological Sites on Fort Hood, Texas: The 1996 Season

DTIC Science & Technology

1999-12-01

alluvium ca. 1100- 1000 B.P. The fact that flood stabilization, pedo - genesis, and accompanying increases in C4 395 National Register Testing at Fort...JVC TK-107OU Color Video Camera mounted on a Zeiss petrographic microscope using a 10X objective lens. The images were saved and imported into Adobe

Enhanced Sorption of PAHs in Natural-Fire-Impacted Sediments from Oriole Lake, California

EPA Science Inventory

Surface sediment cores from Oriole Lake (CA) were analyzed for organic carbon (OC), black carbon (BC), and their δ13C isotope ratios. Sediments displayed high OC(20-25%) and increasing BC concentrations from ∼0.40% (in 1800 C.E.) to ∼0.60% dry weight (in 2000 C.E.). Petrographic...

Provenance of Conglomerates within a Late Cretaceous Turbidite Channel System on the North American Margin: the Rosario Formation, Baja California, Mexico

NASA Astrophysics Data System (ADS)

Dos Santos, Thisiane; Kneller, Benjamin; Morton, Andrew; Armelenti, Garibaldi; Pantopoulos, George; De Ros, Luiz Fernando

2017-04-01

The Rosario Formation forms part of the Peninsular Ranges forearc basin complex, which crops out discontinuously along the Pacific coast of the Baja California Peninsula, Mexico. This study concerns the upper, deep marine part of the Rosario Formation , which includes several slope channel systems, one of these, the San Fernando channel systems consists of five channel complex sets (CCS1 to CCS5), each characterized by three filling stages. Stage I consists of predominantly clast­ and matrix-supported conglomerates, with subordinate medium to coarse grained sandstones. Stage II consists of units of clast-supported conglomerates with subordinate medium to coarse-grained sandstones, separated by mainly thinly-bedded turbidites (intercalation of thin beds of fine-grained sandstones and mudstones). Stage III consists mainly of hemipelagic mudstones. The main objective of this research is to determine source area and to compare the coarse fraction and finer fraction (fragments <2 cm) from conglomerates of each channel set, combining provenance methodology such as heavy minerals, clast counting, geochemistry, bulk petrography and U/Pb in detrital zircons by LA-ICPMS and SHRIMP. The heavy minerals assembly identified were Ca amphibole, epidote, clinozoisite, titanite, garnet, tourmaline, apatite, rutile and zircon, among them amphiboles are by far the most abundant detrital mineral. Clast counting and petrographic characterization showed that the pebble fraction of the conglomerates is constituted at least 18 different, and the majority being composed by pyroclastic, porphyritic volcanic and sandstone rocks. Bulk quantification indicates that the main provenance tectonic mode of the fine fraction of the conglomerates can be interpreted as dissected magmatic arc, with subordinate uplifted basement and recycled orogenic contributions. The preliminary conclusion is that the sedimentary supply to the Rosario Formation was mostly derived from volcanic and plutonic rocks of the Upper Peninsular Ranges Arc complex known as the Alisitos Arc, which follows the western margin of the Peninsular Ranges batholith, as well as from older magmatic arc, and from recycling of sedimentary/metasedimentary terrains.

Sinkhole susceptibility in carbonate rocks of the Apulian karst (southern Italy)

NASA Astrophysics Data System (ADS)

Di Santo, Antonio; Fazio, Nunzio L.; Fiore, Antonio; Lollino, Piernicola; Luisi, Michele; Miccoli, Maria N.; Pagliarulo, Rosa; Parise, Mario; Perrotti, Michele; Pisano, Luca; Spalluto, Luigi; Vennari, Carmela; Vessia, Giovanna

2016-04-01

Apulia region, the foreland of the southern Italian Apennines, is made up of a 6-7 km-thick succession of Mesozoic shallow-water limestones and dolostones, locally covered by thin and discontinuous Tertiary and Quaternary carbonate and clastic deposits. Due to their long subaerial exposure, the Mesozoic carbonate bedrock recorded the development in the subsurface of a dense network of karst cavities, mostly controlled by tectonic discontinuities. As a result, a strong susceptibility to natural sinkholes has to be recorded in Apulia. In addition, the possibility of occurrence of other problems related to the high number of man-made cavities has to be added in the region. A great variety of different typologies of artificial cavities (mostly excavated in the Plio-Pleistocene soft calcarenites) is actually present, including underground quarries, worship sites, oil mills, civilian settlements, etc. Overall, 2200 natural and 1200 artificial cavities, respectively, have been so far surveyed in Apulia. Following the urban development in the last century in Apulia, many of these cavities lie nowadays below densely populated neighborhoods, roads or communication routes. These conditions are at the origin of the main geomorphological hazard for the human society in Apulia, which requires a careful evaluation, aimed at protecting and safeguarding the human life, and at providing the necessary information for a correct land use planning and management. The importance of the sinkhole hazard is further testified by the worrying increase in the number of events during the last 5-6 years. In response to these situations, joint research activities were started by the Institute of Research for Hydrological Protection of the National Research Council (CNR-IRPI) and the Basin Authority of Apulia, aimed at several goals, that include (but are not limited to) the collection of information on natural and anthropogenic sinkholes in Apulia, the implementation of numerical analyses for modelling the instability processes, and the development of charts for a preliminary evaluation of the stability of underground caves. Two distinct approaches were established to take into account the different petrographic, structural and geotechnical features of both the hard and soft carbonate rocks. The approach dealing with hard carbonate rocks (where natural karst caves develop) is based on speleological and geometrical surveys of the caves and on an integrated geological and geomechanical characterization of the carbonate rock mass, aimed at individuating the main critical aspects of the karst caves in terms of likely effects on the society. On the other hand, the approach to verify the stability of soft rocks where artificial cavities have been excavated is mostly dependent upon the peculiar petrographic and geomechanical characteristics of the calcarenite rock mass, typically massive and unaffected by tectonic discontinuities. As a consequence, the traditional analytical methods of rock mass classification fail in these materials, since the rock strength of soft calcarenites is mostly dependent upon sediment texture, porosity type and distribution and degree of cementation. The fluid circulation into the rock mass is also important because the removal of the rock matrix may induce a rapid deterioration of the mechanical behaviour of the rock mass. The approach to the calcarenite is mostly based on the characterization of petrographic and geotechnical parameters by means of direct sampling from the rock walls and in situ surveys (wells, trenches, etc.). Through implementation of the two approaches, our goal is to reconstruct accurate geometrical, geological and geotechnical models for both natural caves and artificial cavities. These models will be useful also to plan specific monitoring activities in order to understand the development of underground instability, and the related evolution through the rock mass, possibly threatening the urban areas and infrastructures above.

Shallow fractionation signature of phase chemistry in Taburiente lavas, La Palma, Canary Islands: Results of MELTS modeling

NASA Astrophysics Data System (ADS)

Guetschow, H. A.; Nelson, B. K.

2002-12-01

Depth of crystal fractionation influences the chemical evolution of ocean island basalts and has significant implications for the physical structures of these volcanoes. In contrast to dominantly shallow systems such as Hawaii, a range of fractionation depths have been reported for Canary Islands lavas. Magmas erupted on La Palma preserve fluid- and melt-inclusion evidence for high-pressure (> 10 kbar) crystallization (Klügel et al., 1998; Hansteen et al., 1998; Nikogosian et al., 2002). If high-pressure fractional crystallization were an early and dominant process, it would generate specific patterns in rock and phase chemistry of eruptive sequences. Alkalic basalts from Taburiente volcano display coherent major element trends consistent with evolution dominated by fractional crystallization while their phenocryst compositions, trace elements, and isotopic trends require mixing between multiple sources. The current model confirms the importance of both fractionation and mixing to achieve the full range of lavas observed. A low-pressure (1 kbar) thermodynamic fractional crystallization model performed with the MELTS (Ghiorso and Sack, 1995) software closely reproduces major element trends from two stratigraphic sequences. This model also predicts the observed sequence of groundmass clinopyroxene compositions and phenocryst zoning reversals. In all low pressure simulations, olivine remains a modally significant liquidus phase during the first 20% and last 30% of the crystallization sequence, resulting in a negative correlation between the CaO and Fo content of olivine. These results are consistent with the presence of olivine phenocrysts that bear petrographic evidence of early crystallization, as well as observed compositional trends of groundmass olivine and clinopyroxene in Taburiente lavas. MELTS models that include an initial period of high pressure (12 kbar) clinopyroxene fractionation produce major element trends comparable to the low pressure model, but also produce high modal volumes of low CaO, high MgO clinopyroxene that are not observed in sections we studied. Removal of such a large quantity of clinopyroxene from the liquid increases the TiO2 and CaO of later-crystallized clinopyroxene to concentrations not observed in our studied sections, and restricts the MgO and FeO* to smaller ranges than observed. Olivine fractionation is restricted to short duration and low abundance late in the crystallization sequence, which is not evident petrographically. The total compositional range of clinopyroxene and olivine crystals observed throughout this suite of rocks is larger than any generated by a single-source MELTS model. Combined with stratigraphically controlled Pb isotope variations it indicates magma mixing and fractionation at low pressures dominates the petrologic diversity in these sections. Hansteen, TH, Klügel, A., Schmincke, H.-U, 1998. Contrib. Min. Pet. 132, 48-64. Klügel, A, 1998. Contrib. Min. Pet. 131, 237-257. Nikogosian, IK, Elliott, T, Touret, JLR. 2002. Chem. Geo. 183, 169-193. Ghiorso, MS, and Sack, RO. Contrib. Min. Pet. 119, 197-212.

FROZEN THIN SECTIONS OF FRESH TISSUE FOR ELECTRON MICROSCOPY, WITH A DESCRIPTION OF PANCREAS AND LIVER

PubMed Central

Christensen, A. Kent

1971-01-01

A simple method has been developed that allows frozen thin sections of fresh-frozen tissue to be cut on a virtually unmodified ultramicrotome kept at room temperature. A bowl-shaped Dewar flask with a knifeholder in its depths replaces the stage of the microtome; a bar extends down into the bowl from the microtome's cutting arm and bears the frozen tissue near its lower end. When the microtome is operated, the tissue passes a glass or diamond knife in the depths of the bowl as in normal cutting. The cutting temperature is maintained by flushing the bowl with cold nitrogen gas, and can be set anywhere from about -160°C up to about -30°C. The microtome is set for a cutting thickness of 540–1000 A. Sections are picked up from the dry knife edge, and are placed on membrane-coated grids, flattened with the polished end of a copper rod, and either dried in nitrogen gas or freeze-dried. Throughout the entire process the tissue is kept cold and does not come in contact with any solvent. The morphology seen in frozen thin sections of rat pancreas and liver generally resembles that in conventional preparations, although freezing damage and low contrast limit the detail that can be discerned. Among unusual findings is a frequent abundance of mitochondrial granules in material prepared by this method. PMID:4942776

Thinness in young schoolchildren in Serbia: another case of the double burden of malnutrition?

PubMed

Djordjic, Visnja; Jorga, Jagoda; Radisavljevic, Snezana; Milanovic, Ivana; Bozic, Predrag; Ostojic, Sergej M

2018-04-01

Thinness is rarely highlighted or regularly monitored among children in developed countries although it may be rather frequent and pose a significant risk to children's health. We aimed to describe the prevalence of mild, moderate and severe thinness among young Serbian schoolchildren. Cross-sectional study of schoolchildren aged 6-9 years. Children were assessed for weight, height and BMI as part of the WHO European Childhood Obesity Surveillance Initiative in Serbia. Thinness grades were defined as gender- and age-specific cut-offs for BMI according to the International Obesity Task Force criteria. Serbia, September to November 2015. Students (n 4861) in grades 2 and 3 (6-9 years, 2397 girls). Overall prevalence of thinness in Serbian schoolchildren was 9·6 %. Mild thinness was clearly the largest category with a prevalence of 7·6 %, moderate thinness was present in 1·7 % of children and severe thinness was found in 0·3 % of children. OR indicated a significant risk of being thin for girls (1·44 times higher compared with boys) and children attending schools with no health-focused educational programme (1·57 times more likely to be thin than peers enrolled in schools with such programmes). In addition, OR for thinness tended to be 1·23 times higher in children living in an economically disadvantaged region of Serbia (P=0·06). A rather high prevalence of thinness highlights this malnutrition disorder as an emerging health issue that should trigger public health policies to tackle thinness, especially in girls of young age and children living in economically disadvantaged areas.

Ultrasonic Nondestructive Evaluation Techniques Applied to the Quantitative Characterization of Textile Composite Materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1997-01-01

In this Progress Report, we describe our recent developments of advanced ultrasonic nondestructive evaluation methods applied to the characterization of anisotropic materials. We present images obtained from experimental measurements of ultrasonic diffraction patterns for a thin woven composite in an immersion setup. In addition, we compare apparent signal loss measurements of the thin woven composite for phase-sensitive and phase-insensitive detection methods. All images of diffraction patterns have been included on the accompanying CD-ROM in the Adobe(Trademark) Portable Document Format (PDF). Due to the extensive amount of data, however, hardcopies of only a small representative selection of the images are included within the printed report. This Progress Report presents experimental results that support successful implementation of single element as well as one and two-dimensional ultrasonic array technologies for the inspection of textile composite structures. In our previous reports, we have addressed issues regarding beam profiles of ultrasonic pressure fields transmitted through a water reference path and transmitted through a thin woven composite sample path. Furthermore, we presented experimental results of the effect of a thin woven composite on the magnitude of an insonifying ultrasonic pressure field. In addition to the study of ultrasonic beam profiles, we consider issues relevant to the application of single-element, one-dimensional, and two-dimensional array technologies towards probing the mechanical properties of advanced engineering composites and structures. We provide comparisons between phase-sensitive and phase-insensitive detection methods for determination of textile composite structure parameters. We also compare phase-sensitive and phase-insensitive - - ---- ----- apparent signal loss measurements in an effort to study the phenomenon of phase cancellation at the face of a finite-aperture single-element receiver. Furthermore, in this Progress Report we extend our work on ultrasonic beam profile issues through investigation of the phase fronts of the pressure field. In Section H of this Progress Report we briefly describe the experimental arrangement and methods for data acquisition of the ultrasonic diffraction patterns upon transmission through a thin woven composite. Section III details the analysis of the experimental data followed by the experimental results in Section IV. Finally, a discussion of the observations and conclusions is found in Section V.

An acetate precursor process for BSCCO (2223) thin films and coprecipitated powders

NASA Technical Reports Server (NTRS)

Haertling, Gene H.

1992-01-01

Since the discovery of high temperature superconducting oxides much attention has been paid to finding better and useful ways to take advantage of the special properties exhibited by these materials. One such process is the development of thin films for engineering applications. Another such process is the coprecipitation route to producing superconducting powders. An acetate precursor process for use in thin film fabrication and a chemical coprecipitation route to Bismuth based superconducting materials has been developed. Data obtained from the thin film process were inconclusive to date and require more study. The chemical coprecipitation method of producing bulk material is a viable method, and is preferred over the previously used solid state route. This method of powder production appears to be an excellent route to producing thin section tape cast material and screen printed devices, as it requires less calcines than the oxide route to produce quality powders.

Insect Thin Films as Sun Blocks, Not Solar Collectors

NASA Astrophysics Data System (ADS)

Koon, Daniel W.; Crawford, Andrew B.

2000-05-01

We measured the visible reflectance spectra of whole wing sections from three species of iridescent butterflies and moths, for normal incidence, integrated over all reflected angles. In this manner, we separated the optics of the thin films causing the iridescence from the optics of the rest of the scale. We found that iridescence reduces solar absorption by the wing in all cases, typically by approximately 20% or less, in contrast to claims by Miaoulis and Heilman Ann. Entomol. Soc. Am. 91, 122 (1998) that the thin-film structures that produce iridescence act as solar collectors.

Spanwise transition section for blended wing-body aircraft

NASA Technical Reports Server (NTRS)

Hawley, Arthur V. (Inventor)

1999-01-01

A blended wing-body aircraft includes a central body, a wing, and a transition section which interconnects the body and the wing on each side of the aircraft. The two transition sections are identical, and each has a variable chord length and thickness which varies in proportion to the chord length. This enables the transition section to connect the thin wing to the thicker body. Each transition section has a negative sweep angle.

Thin-sectioning and analysis of fine-grained meteoritic materials

NASA Technical Reports Server (NTRS)

Brooks, Donald A. (Editor); Bradley, John P.

1992-01-01

The overall theme of the work was the identification of the sources and formation/aggregation mechanisms of the various classes of interplanetary dust particles (IDP's) and to clarify the relationship between IDP's and conventional meteorites. IDP's are believed to be derived from a much broader range of parent bodies than conventional meteorites. Some of these parent bodies (e.g., comets) have escaped that post accretional processing that has affected the parent bodies of meteorites. Therefore, IDP's are likely to preserve a record of early solar system and possibly presolar grain forming reactions. Using analytical electron microscopy (AEM) and more recently micro-infrared (IR) microspectroscopy to examine ultramicrotomed thin sections, we have addressed the questions of IDP formation mechanisms, sources, and their relationship to conventional meteorites. The following sections describe specific findings resulting from these studies.

Gender-Related Discourses as Mediators in the Association between Internalization of the Thin-Body Ideal and Indicants of Body Dissatisfaction and Disordered Eating

ERIC Educational Resources Information Center

Morrison, Todd G.; Sheahan, Emer E.

2009-01-01

This study examined whether the gender-related discourses of self-objectification, self-silencing, and anger suppression mediated the association between internalization of the thin-body ideal and body dissatisfaction and eating pathology. We employed a cross-sectional design to study both university (n = 140) and community (n = 76) samples of…

Effects of late rotation thinning on light availability and red oak regeneration within a minor stream bottom in Mississippi

Treesearch

Ellen M. Boerger; Brent R. Frey; Andrew W. Ezell; Tracy Hawkins

2015-01-01

Recent studies suggest a troubling decline in the abundance of red oak species (Quercus spp., Section Erythrobalanus) in bottomland forests of the southeastern United States. We assessed red oak advance regeneration and associated tree species in relation to light availability in a 77-year-old oak-dominated stand 5 years after late rotation thinning. Residual basal...

Recommended procedures and techniques for the petrographic description of bituminous coals

USGS Publications Warehouse

Chao, E.C.T.; Minkin, J.A.; Thompson, C.L.

1982-01-01

Modern coal petrology requires rapid and precise description of great numbers of coal core or bench samples in order to acquire the information required to understand and predict vertical and lateral variation of coal quality for correlation with coal-bed thickness, depositional environment, suitability for technological uses, etc. Procedures for coal description vary in accordance with the objectives of the description. To achieve our aim of acquiring the maximum amount of quantitative information within the shortest period of time, we have adopted a combined megascopic-microscopic procedure. Megascopic analysis is used to identify the distinctive lithologies present, and microscopic analysis is required only to describe representative examples of the mixed lithologies observed. This procedure greatly decreases the number of microscopic analyses needed for adequate description of a sample. For quantitative megascopic description of coal microlithotypes, microlithotype assemblages, and lithotypes, we use (V) for vitrite or vitrain, (E) for liptite, (I) for inertite or fusain, (M) for mineral layers or lenses other than iron sulfide, (S) for iron sulfide, and (X1), (X2), etc. for mixed lithologies. Microscopic description is expressed in terms of V representing the vitrinite maceral group, E the exinite group, I the inertinite group, and M mineral components. volume percentages are expressed as subscripts. Thus (V)20(V80E10I5M5)80 indicates a lithotype or assemblage of microlithotypes consisting of 20 vol. % vitrite and 80% of a mixed lithology having a modal maceral composition V80E10I5M5. This bulk composition can alternatively be recalculated and described as V84E8I4M4. To generate these quantitative data rapidly and accurately, we utilize an automated image analysis system (AIAS). Plots of VEIM data on easily constructed ternary diagrams provide readily comprehended illustrations of the range of modal composition of the lithologic units making up a given coal bed. The use of bulk-specific-gravity determinations is alo recommended for identification and characterization of the distinctive lithologic units. The availability of an AIAS also enhances the capability to acquire textural information. Ranges of size of maceral and mineral grains can be quickly and precisely determined by use of an AIAS. We assume that shape characteristics of coal particles can also be readily evaluated by automated image analysis, although this evaluation has not yet been attempted in our laboratory. Definitive data on the particulate mineral content of coal constitute another important segment of petrographic description. Characterization of mineral content may be accomplished by optical identification, electron microprobe analysis, X-ray diffraction, and scanning and transmission electron microscopy. Individual mineral grains in place in polished blocks or polished this sections, or separated from the coal matrix by sink-float methods are studied by analytical techniques appropriate to the conditions of sampling. Finally, whenever possible, identification of the probable genus or plant species from which a given coal component is derived will add valuable information and meaning to the petrographic description. ?? 1982.

Plasmonic excitation-assisted optical and electric enhancement in ultra-thin solar cells: the influence of nano-strip cross section

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabaeian, Mohammad, E-mail: sabaiean@scu.ac.ir; Heydari, Mehdi; Ajamgard, Narges

The effects of Ag nano-strips with triangle, rectangular and trapezoid cross sections on the optical absorption, generation rate, and short-circuit current density of ultra-thin solar cells were investigated. By putting the nano-strips as a grating structure on the top of the solar cells, the waveguide, surface plasmon polariton (SPP), and localized surface plasmon (LSP) modes, which are excited with the assistance of nano-strips, were evaluated in TE and TM polarizations. The results show, firstly, the TM modes are more influential than TE modes in optical and electrical properties enhancement of solar cell, because of plasmonic excitations in TM mode. Secondly,more » the trapezoid nano-strips reveal noticeable impact on the optical absorption, generation rate, and short-circuit current density enhancement than triangle and rectangular ones. In particular, the absorption of long wavelengths which is a challenge in ultra-thin solar cells is significantly improved by using Ag trapezoid nano-strips.« less

Effect of angle of deposition on the Fractal properties of ZnO thin film surface

NASA Astrophysics Data System (ADS)

Yadav, R. P.; Agarwal, D. C.; Kumar, Manvendra; Rajput, Parasmani; Tomar, D. S.; Pandey, S. N.; Priya, P. K.; Mittal, A. K.

2017-09-01

Zinc oxide (ZnO) thin films were prepared by atom beam sputtering at various deposition angles in the range of 20-75°. The deposited thin films were examined by glancing angle X-ray diffraction and atomic force microscopy (AFM). Scaling law analysis was performed on AFM images to show that the thin film surfaces are self-affine. Fractal dimension of each of the 256 vertical sections along the fast scan direction of a discretized surface, obtained from the AFM height data, was estimated using the Higuchi's algorithm. Hurst exponent was computed from the fractal dimension. The grain sizes, as determined by applying self-correlation function on AFM micrographs, varied with the deposition angle in the same manner as the Hurst exponent.

Handling Golgi-impregnated tissue for light microscopy.

PubMed

Berbel, P J; Fairén, A

1983-08-08

The use of cyanocrylic glue to fix pieces of Golgi-stained nervous tissue on a paraffin blank is proposed for obtaining thick sections of unembedded tissue with a sliding microtome. This procedure makes correct orientation of the tissue easy during sectioning and makes it possible to obtain tissue sections quickly. The sections are flat-mounted using epoxy resin, resulting in permanent preparations with excellent optical properties and enabling further thin-sectioning for light and electron microscopic studies.

Allanite and epidote weathering at the Coweeta hydrologic laboratory, western North Carolina, U.S.A.

Treesearch

Jason R. Price; Michael L. Velbel; Lina C. Pantino

2005-01-01

Allanite and epidote occur in the parent rocks of weathered regolith at the Coweeta Hydrologic Laboratory in North Carolina and exhibit different responses to weathering. Petrographically, epidote and allanite are identical at Coweeta, and only with additional analytical techniques (e.g., EDS or LAICP- MS) can the two be distinguished. Allanite is more...

Geochemistry and petrography of the MacAlpine Hills lunar meteorites

NASA Technical Reports Server (NTRS)

Lindstrom, Marilyn M.; Mckay, David S.; Wentworth, Susan J.; Martinez, Rene R.; Mittlefehldt, David W.; Wang, Ming-Sheng; Lipschutz, Michael E.

1991-01-01

MacAlpine Hills 88104 and 88105, anorthositic lunar meteorites recovered form the same area in Antartica, are characterized. Petrographic studies show that MAC88104/5 is a polymict breccia dominated by impact melt clasts. It is better classified as a fragmental breccia than a regolith breccia. The bulk composition is ferroan and highly aluminous (Al2O3-28 percent).

Introduction to the Apollo collections. Part 1: Lunar igneous rocks

NASA Technical Reports Server (NTRS)

Mcgee, P. E.; Warner, J. L.; Simonds, C. H.

1977-01-01

The basic petrographic, chemical, and age data is presented for a representative suite of igneous rocks gathered during the six Apollo missions. Tables are given for 69 samples: 32 igneous rocks and 37 impactites (breccias). A description is given of 26 basalts, four plutonic rocks, and two pyroclastic samples. The textural-mineralogic name assigned each sample is included.

Large Meteorite Impacts and Planetary Evolution

NASA Technical Reports Server (NTRS)

1997-01-01

The present volume of abstracts of conference papers discusses topics associated with the role of meteorite impacts on the Earth, the moon, and Titan. Particular attention is given to the description of the impact damage and the description of the actual craters. Attention is also given to the Sudbury structure, and the Chicxulub crater. Mineralogical, geophysical, petrographic, seismic and image data are described and discussed.

The properties of thin-section, four-point-contact ball bearings in space

NASA Technical Reports Server (NTRS)

Rowntree, R. A.

1985-01-01

Thin section, four-point-contact ball bearings are increasinly employed in spacecraft mechanisms because of the potential advantages they offer. However, litte was previously known of their torque, thermal conductance and stiffness properties at conditions anticipated for their use in space. An investigation of these properties are described. It was found that frictional (Coulomb) torque, thermal conductance and stiffness all show marked dependence on the bearing preload, the housing design, the bearing external fit (i.e., free fit or interference) and on the thermal gradient across the races. Optimum bearing performance is achieved only if these properties are well understood. The necessary data to understand these properties are provided.

[Thin-section computed tomography of the bronchi; 2. Right upper lobe and left upper division].

PubMed

Matsuoka, Y; Ookubo, T; Ohtomo, K; Nishikawa, J; Kojima, K; Oyama, K; Yoshikawa, K; Iio, M

1990-02-01

Thin (2mm) section contiguous computed tomographic (CT) scans were obtained through the bronchi of the right upper lobe and the left upper division in 30 patients. All segmental bronchi were identified. The right subsegmental bronchi were identified in 100%, and the left subsegmental bronchi in 97%. The type of the orifice of the right bronchus was trifurcated (53%), the extension of B1 was apicoanterior (50%), and the size of B2b was equal to B3a (63%). The extension of the left B3 was subapicoanterior (38%), and the size of B1+2c was equal to B3a (62%).

Space Shuttle Stiffener Ring Foam Failure, a Non-Conventional Approach

NASA Technical Reports Server (NTRS)

Howard, Philip M.

2007-01-01

The Space Shuttle makes use of the excellent properties of rigid polyurethane foam for cryogenic tank insulation and as structural protection on the solid rocket boosters. When foam applications debond, classical methods of analysis do not always provide root cause of the failure of the foam. Realizing that foam is the ideal media to document and preserve its own mode of failure, thin sectioning was seen as a logical approach for foam failure analysis. Thin sectioning in two directions, both horizontal and vertical to the application, was chosen to observe the three dimensional morphology of the foam cells. The cell foam morphology provided a much greater understanding of the failure modes than previously achieved.

The impact of fire on the Late Paleozoic Earth system

PubMed Central

Glasspool, Ian J.; Scott, Andrew C.; Waltham, David; Pronina, Natalia; Shao, Longyi

2015-01-01

Analyses of bulk petrographic data indicate that during the Late Paleozoic wildfires were more prevalent than at present. We propose that the development of fire systems through this interval was controlled predominantly by the elevated atmospheric oxygen concentration (p(O2)) that mass balance models predict prevailed. At higher levels of p(O2), increased fire activity would have rendered vegetation with high-moisture contents more susceptible to ignition and would have facilitated continued combustion. We argue that coal petrographic data indicate that p(O2) rather than global temperatures or climate, resulted in the increased levels of wildfire activity observed during the Late Paleozoic and can, therefore, be used to predict it. These findings are based upon analyses of charcoal volumes in multiple coals distributed across the globe and deposited during this time period, and that were then compared with similarly diverse modern peats and Cenozoic lignites and coals. Herein, we examine the environmental and ecological factors that would have impacted fire activity and we conclude that of these factors p(O2) played the largest role in promoting fires in Late Paleozoic peat-forming environments and, by inference, ecosystems generally, when compared with their prevalence in the modern world. PMID:26442069

The impact of fire on the Late Paleozoic Earth system.

PubMed

Glasspool, Ian J; Scott, Andrew C; Waltham, David; Pronina, Natalia; Shao, Longyi

2015-01-01

Analyses of bulk petrographic data indicate that during the Late Paleozoic wildfires were more prevalent than at present. We propose that the development of fire systems through this interval was controlled predominantly by the elevated atmospheric oxygen concentration (p(O2)) that mass balance models predict prevailed. At higher levels of p(O2), increased fire activity would have rendered vegetation with high-moisture contents more susceptible to ignition and would have facilitated continued combustion. We argue that coal petrographic data indicate that p(O2) rather than global temperatures or climate, resulted in the increased levels of wildfire activity observed during the Late Paleozoic and can, therefore, be used to predict it. These findings are based upon analyses of charcoal volumes in multiple coals distributed across the globe and deposited during this time period, and that were then compared with similarly diverse modern peats and Cenozoic lignites and coals. Herein, we examine the environmental and ecological factors that would have impacted fire activity and we conclude that of these factors p(O2) played the largest role in promoting fires in Late Paleozoic peat-forming environments and, by inference, ecosystems generally, when compared with their prevalence in the modern world.

Chemical weathering and diagenesis of a cold desert soil from Wright Valley, Antarctica - An analog of Martian weathering processes

NASA Technical Reports Server (NTRS)

Gibson, E. K.; Mckay, D. S.; Wentworth, S. J.

1983-01-01

Weathering, diagenesis, and chemical alteration of a soil profile from the Dry Valleys of Antarctica are investigated as an analog to soil development within the Martian regolith. Soil samples from a soil pit one meter deep on Prospect Mesa, Wright Valley, are examined for their major element concentrations, water-soluble cations and anions, carbon, sulfur, and water concentrations, and related petrographic characteristics of weathering in a cold, dry environment. A petrographic study of the samples suggests that most silicate mineral and lithic fragments exhibit some degree of alteration. Chemical alteration occurs both in samples above and within the permanently frozen zone. The concentrations of water-soluble cations, for example, Na(+), K(+), Ca(2+), and anions, Cl(-), SO4(2-), NO3(-), are found to decrease significantly from the surface to the permanently frozen zone, suggesting a major movement of water-soluble species. It is also found that enrichments in secondary mineral abundances correlate with the water soluble ion concentrations. The formation of zeolites is seen throughout the soil column; these, it is thought, may be reservoirs for volatile storage within the regolith.

Petrological features of selected components of the Cergowa sandstones (Outer Carpathians) recorded by scanning electron microscopy - preliminary study

NASA Astrophysics Data System (ADS)

Pszonka, Joanna

2017-11-01

The scanning electron microscope analysis of the Cergowa sandstones brings new data on their petrological features and chemical composition. Previous work in standard petrographic examination, e.g. polarising (PL) or cathodoluminescence (CL) microscopy, displayed limited information on grain surface topography and only assumptions to their geochemistry. Both identification and characterisation of minerals are fundamental in the progress of mining and minerals processing systems. Detrital grains of the Cergowa sandstones are bound by calcite and dolomitic cement and commonly corroded by diagenetic fluids, however, in varying degrees, which is illustrated here by feldspar, quartz and dolomite minerals. Dissolution processes of marginal parts of these mineral grains resulted in corrosion, which increased the contact surface between the grains and the cement. The difference in resistance to these processes was observed not only among distinct groups of minerals, but also within the group of feldspars: between K-feldspars and minerals of plagioclase. That combination resulted in exceptionally strong cementation of the Cergowa sandstones, which is expressed by their high hardness and resistance to abrasion, freezing, and thawing. Inherent parameters of sandstones are characterised by their petrographical properties.

Hardgrove grindability study of Powder River Basin and Appalachian coal components in the blend to a midwestern power station

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padgett, P.L.; Hower, J.C.

1996-12-31

Five coals representing four distinct coal sources blended at a midwestern power station were subjected to detailed analysis of their Hardgrove grindability. The coals are: a low-sulfur, high volatile A bituminous Upper Elkhorn No. 3 coal (Pike County, KY); a medium-sulfur, high volatile A bituminous Pittsburgh coal (southwestern PA); a low-sulfur, subbituminous Wyodak coal from two mines in the eastern Powder River Basin (Campbell County, WY). The feed and all samples processed in the Hardgrove grindability test procedure were analyzed for their maceral and microlithotype content. The high-vitrinite Pittsburgh coal and the relatively more petrographically complex Upper Elkhorn No. 3more » coal exhibit differing behavior in grindability. The Pittsburgh raw feed, 16x30 mesh fraction (HGI test fraction), and the {minus}30 mesh fraction (HGI reject) are relatively similar petrographically, suggesting that the HGI test fraction is reasonably representative of the whole feed. The eastern Kentucky coal is not as representative of the whole feed, the HGI test fraction having lower vitrinite than the rejected {minus}30 mesh fraction. The Powder River Basin coals are high vitrinite and show behavior similar to the Pittsburgh coal.« less

Iodine-xenon, chemical, and petrographic studies of Semarkona chondrules - Evidence for the timing of aqueous alteration

NASA Technical Reports Server (NTRS)

Swindle, T. D.; Grossman, J. N.; Olinger, C. T.; Garrison, D. H.

1991-01-01

The relationship of the I-Xe system of the Semarkona meteorite to other measured properties is investigated via INAA, petrographic, and noble-gas analyses on 17 chondrules from the meteorite. A range of not less than 10 Ma in apparent I-Xe ages is observed. The three latest apparent ages fall in a cluster, suggesting the possibility of a common event. It is argued that the initial I-129/I-127 ratio (R0) is related to chondrule type and/or mineralogy, with nonporphyritic and pyroxene-rich chondrules showing evidence for lower R0s than porphyritic and olivine-rich chondrules. Chondrules with sulfides on or near the surface have lower R0s than other chondrules. The He-129/Xe-132 ratio in the trapped Xe component anticorrelates with R0, consistent with the evolution of a chronometer in a closed system or in multiple systems. It is concluded that the variations in R0 represent variations in ages, and that later events, possibly aqueous alteration, preferentially affected chondrules with nonporphyritic textures and/or sulfide-rich exteriors about 10 Ma after the formation of the chondrules.

Diagenesis and evolution of microporosity of Middle-Upper Devonian Kee Scarp reefs, Norman Wells, Northwest Territories, Canada: Petrographic and chemical evidence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Aasm, I.S.; Azmy, K.K.

The Middle-Upper Devonian Kee Scarp reef complexes of Norman Wells, Northwest Territories, Canada, are oil-producing, stromatoporoid-dominated carbonates. Episodic increases in the rate of sea level rise produced multiple cycles of reef growth that exhibit backstepping characteristics. These carbonates, composed of invariably altered limestones, have original interskeletal, intraskeletal, and intergranular porosity, mostly occluded by nonferroan, dull luminescent cements. Secondary porosity, represented by micropores of various types, developed during diagenesis by aggrading neomorphism and dissolution. The micropores represent the main reservoir porosity in the Kee Scarp limestone. Petrographic, chemical, and isotopic studies of Kee Scarp reef components reveal a complex diagenetic historymore » involving marine fluids modified by increasing water/rock interaction and burial. Neomorphic stabilization of skeletal components caused further depletion in {gamma}{sup 18}O but very little change in {gamma}{sup 13}C, an argument for modification of the original marine fluids with increasing burial. Variations in magnitude of water/rock interaction with depth, facies changes, and porosity modifications probably exerted some control on fractionation and distribution of stable isotopes and trace elements in reef components.« less

Petrography and the REE-composition of apatite in the Paleoproterozoic Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia

NASA Astrophysics Data System (ADS)

Joosu, Lauri; Lepland, Aivo; Kreitsmann, Timmu; Üpraus, Kärt; Roberts, Nick M. W.; Paiste, Päärn; Martin, Adam P.; Kirsimäe, Kalle

2016-08-01

The first globally significant phosphorous-rich deposits appear in the Paleoproterozoic at around 2 Ga, however, the specific triggers leading to apatite precipitation are debated. We examine phosphorous-rich rocks (up to 8 wt% P2O5) in 1.98-1.92 Ga old Pilgujärvi Sedimentary Formation, Pechenga Greenstone Belt, Russia. Phosphates in these rocks occur as locally derived and resedimented sand-to-gravel/pebble sized grains consisting of apatite-cemented muddy sediments. Phosphatic grains can be subdivided into four petrographic types (A-D), each has a distinct REE signature reflecting different early-to-late diagenetic conditions and/or metamorphic overprint. Pyrite containing petrographic type D, which typically has a flat REE pattern, negative Ce anomaly and positive Eu anomaly, is the best preserved of the four types and best records conditions present during apatite precipitation. Type D phosphatic grains precipitated under (sub)oxic basinal conditions with a significant hydrothermal influence. These characteristics are similar to Zaonega Formation phosphates of NW Russia's Onega Basin, and consistent with phosphogenesis triggered by the development of anoxic(sulfidic)-(sub)oxic redoxclines at shallow sediment depth during the Paleoproterozoic.

Synthesis of 2D Metal Chalcogenide Thin Films through the Process Involving Solution-Phase Deposition.

PubMed

Giri, Anupam; Park, Gyeongbae; Yang, Heeseung; Pal, Monalisa; Kwak, Junghyeok; Jeong, Unyong

2018-04-24

2D metal chalcogenide thin films have recently attracted considerable attention owing to their unique physicochemical properties and great potential in a variety of applications. Synthesis of large-area 2D metal chalcogenide thin films in controllable ways remains a key challenge in this research field. Recently, the solution-based synthesis of 2D metal chalcogenide thin films has emerged as an alternative approach to vacuum-based synthesis because it is relatively simple and easy to scale up for high-throughput production. In addition, solution-based thin films open new opportunities that cannot be achieved from vacuum-based thin films. Here, a comprehensive summary regarding the basic structures and properties of different types of 2D metal chalcogenides, the mechanistic details of the chemical reactions in the synthesis of the metal chalcogenide thin films, recent successes in the synthesis by different reaction approaches, and the applications and potential uses is provided. In the last perspective section, the technical challenges to be overcome and the future research directions in the solution-based synthesis of 2D metal chalcogenides are discussed. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ferroelectric and piezoelectric thin films and their applications for integrated capacitors, piezoelectric ultrasound transducers and piezoelectric switches

NASA Astrophysics Data System (ADS)

Klee, M.; Boots, H.; Kumar, B.; van Heesch, C.; Mauczok, R.; Keur, W.; de Wild, M.; van Esch, H.; Roest, A. L.; Reimann, K.; van Leuken, L.; Wunnicke, O.; Zhao, J.; Schmitz, G.; Mienkina, M.; Mleczko, M.; Tiggelman, M.

2010-02-01

Ferroelectric and piezoelectric thin films are gaining more and more importance for the integration of high performance devices in small modules. High-K 'Integrated Discretes' devices have been developed, which are based on thin film ferroelectric capacitors integrated together with resistors and ESD protection diodes in a small Si-based chip-scale package. Making use of ferroelectric thin films with relative permittivity of 950-1600 and stacking processes of capacitors, extremely high capacitance densities of 20-520 nF/mm2, high breakdown voltages up to 140 V and lifetimes of more than 10 years at operating voltages of 5 V and 85°C are achieved. Thin film high-density capacitors play also an important role as tunable capacitors for applications such as tuneable matching circuits for RF sections of mobile phones. The performance of thin film tuneable capacitors at frequencies between 1 MHz and 1 GHz is investigated. Finally thin film piezoelectric ultrasound transducers, processed in Si- related processes, are attractive for medical imaging, since they enable large bandwidth (>100%), high frequency operation and have the potential to integrate electronics. With these piezoelectric thin film ultrasound transducers real time ultrasound images have been realized. Finally, piezoelectric thin films are used to manufacture galvanic MEMS switches. A model for the quasi-static mechanical behaviour is presented and compared with measurements.

Energy flux and hydrogeology of thermal anomalies in the Gulf of Mexico Basin: South Texas example

NASA Astrophysics Data System (ADS)

Sharp, J. M., Jr.

1994-03-01

This report covers the period from 1 September 1993 through 28 February 1994. The last Technical Progress Report was submitted in September 1993. In this period, we have focused our efforts on the following activities: (1) Finalizing collection of radiogenic heat production data; (2) Evaluating petrographic controls on thermal conductivity; (3) Modeling one-dimensional heat conduction with sources; (4) Completing base geologic cross-section; (5) Acquiring pressure data to augment data base; (6) Putting map and well data into digital format for analysis; (7) Analyzing salinity, temperate and fluid potential data for propensity of free convection; (8) Finalizing preliminary investigation into depressurization of reservoirs; (9) Preparing presentations for AAPG meeting in Denver; (10) Presenting results at the Geological Society of America Meeting in Boston (October 1993); (11) Collaborating with project members of the DOE funded Global Basins Research Network who are working on a project in the Eugene Island Block, offshore Louisiana; and (12) Collaborating with others working on research in the Gulf of Mexico Basin in our Department and with CSIRO scientists in Adelaide, Australia.

Analytical results from samples collected during coal-bed methane exploration drilling in Caldwell Parish, Louisiana

USGS Publications Warehouse

Warwick, Peter D.; Breland, F. Clayton; Hackley, Paul C.; Dulong, Frank T.; Nichols, Douglas J.; Karlsen, Alexander W.; Bustin, R. Marc; Barker, Charles E.; Willett, Jason C.; Trippi, Michael H.

2006-01-01

In 2001, and 2002, the U.S. Geological Survey (USGS) and the Louisiana Geological Survey (LGS), through a Cooperative Research and Development Agreement (CRADA) with Devon SFS Operating, Inc. (Devon), participated in an exploratory drilling and coring program for coal-bed methane in north-central Louisiana. The USGS and LGS collected 25 coal core and cuttings samples from two coal-bed methane test wells that were drilled in west-central Caldwell Parish, Louisiana. The purpose of this report is to provide the results of the analytical program conducted on the USGS/LGS samples. The data generated from this project are summarized in various topical sections that include: 1. molecular and isotopic data from coal gas samples; 2. results of low-temperature ashing and X-ray analysis; 3. palynological data; 4. down-hole temperature data; 5. detailed core descriptions and selected core photographs; 6. coal physical and chemical analytical data; 7. coal gas desorption results; 8. methane and carbon dioxide coal sorption data; 9. coal petrographic results; and 10. geophysical logs.

Petrographic and petrological study of lunar rock materials

NASA Technical Reports Server (NTRS)

Winzer, S. R.

1976-01-01

Samples returned from Apollo 14 (14171, 14305, 14319), Apollo 15 (15255), Apollo 16 (61175, 67455), and Apollo 17 (77215) were studied optically and selected polished sections by SEM/Microprobe. Splits and separates from 77215, 67455, 61175 and 15255 were prepared; 77215 and 67455 were analyzed for major, minor and LIL trace elements. The data indicate that 77215, a noritic breccia clast found in the Station7 boulder, is a norite cumulate similar to and probably derived from the same body as 78235. The Apollo 17 boulders are found to be part of the same melt sheet, which was formed by a major impact event, possibly Serenitatis, about 4 B. Y. ago. The Apollo 14 and 16 breccias are polymict, their clast populations indicating quite different provenance. The Apollo 14 breccias are possibly the result of multiple impacts, while the other breccias studied appear to have been formed by single impacts. ANT suite clasts included in 61175 are, for the most part, granulites resulting from subsolidus recrystallization of norites, anorthosites or gabbros. This metamorphism appears to have occurred prior to the impact event forming 61175.

Computer Program for Steady Transonic Flow over Thin Airfoils by Finite Elements

DTIC Science & Technology

1975-10-01

COMPUTER PROGRAM FOR STEADY JJ TRANSONIC FLOW OVER THIN AIRFOILS BY g FINITE ELEMENTS • *q^^ r ̂ c HUNTSVILLE RESEARCH & ENGINEERING CENTER...jglMMi B Jun’ INC ORGANIMTION NAME ANO ADDRESS Lö^kfteed Missiles & Space Company, Inc. Huntsville Research & Engineering Center,^ Huntsville, Alab...This report was prepared by personnel in the Computational Mechamcs Section of the Lockheed Missiles fc Space Company, Inc.. Huntsville Research