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The relationship of scheelite mineralization to late-stage changes in selected tactites in southwestern MontanaCrump, Terry Richard, 1946-, Crump, Terry Richard, 1946- January 1976 (has links)
No description available.
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Geochemical investigation of Rosita Hills volcanic complex, Custer County, ColoradoSmalley, Joseph January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
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Chemical studies of the lost rocks of the Lake Dufault Mine, Quebec.Sakrison, Herbert Charles. January 1966 (has links)
No description available.
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Chemical studies of the lost rocks of the Lake Dufault Mine, Quebec.Sakrison, Herbert Charles. January 1966 (has links)
No description available.
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The characterisation of calcrete based on its environmental settings within selected regions of the Kalahari, Southern AfricaShaw, Alexander Iain January 2009 (has links)
Chemical sediments in a variety of geomorphic environments (pedogenic, fluvial, palustrine, lacustrine and pan) were investigated from seven regions (SW Kalahari, Kgalagadi, Kalkweissrand, Etosha, Linyanti, Okavango and Ngami) in the Kalahari of southern Africa. These primary and multi-phase sediments were characterised by a range of pure and intergrade silcrete, calcrete and dolocrete fabrics which contained an array of structures indicative of the crystalline and biogenic processes responsible for their precipitation, epigenesis and paragenesis. Petrography, mineralogy and isotope geochemistry provided significant insight regarding the environmental and geochemical conditions at the time of precipitation. Petrography indicated that the majority of chemical sediments were undergoing epigenetic modification as a consequence of the desiccation induced transition from phreatic to vadose diagenetic and geochemical conditions. The role of rapidly infiltrating meteoric water, associated with unstable wetting fronts, is believed to be instrumental in vadose diagenesis and the precipitation of crystalline/alpha fabric carbonate. Salinisation within the capillary fringe and deeper vadose zone is believed to be responsible for the sequence dolomitisation of crystalline calcite within mature sequences. Highly saline pan conditions instigate the precipitation of authigenic dolomite, calcite and K-feldspar within the surface sediments and authigenic silica at depth. Phreatic water beneath the islands, floodplains and fluvial systems of the Okavango, which undergoes evapotranspirational and transmission salinisation and ultimately terminal desiccation, are similarly precipitating silcrete. Pedogenic processes principally associated with C<sub>4</sub> vegetation are responsible for the gratification of carbonate mud within desiccating lacustrine, palustrine and pan sediments. Within the thin sandy Kalahari soils, pedogenesis is limited, but biogenic/beta fabric precipitation linked to mycorrihizae and tree/shrub savanna vegetation is instrumental in the formation of hardpans and the modification of upper calcrete horizons. The dominance of a distinct assemblage (smectite/kaolinite or sepiolite/palygorskite) of authigenic clay minerals present within all the environments provides evidence of semi-arid precipitation within Mg and Ca enriched saline/rapidly evaporating water or brackish/reduced permeability environments.
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Algorithms for numerical modeling and inversion of multi-phase fluid flow and electromagnetic measurementsAlpak, Faruk Omer 28 August 2008 (has links)
Not available / text
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Automated stratigraphic classification and feature detection from images of borehole coresVan der Walt, Stefan Johann 03 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2005. / This thesis describes techniques proposed for analysing images of borehole
cores. We address two problems: firstly, the automated stratigraphic classification
of cores based on texture and secondly, the location of thin chromitite
layers hidden in pyroxenite cores.
Texture features of different rock types are extracted using wavelets, the
theory of which provides an intuitive and powerful tool for this purpose. A
Bayesian classifier is trained and used to discriminate between different samples.
Thin, planar chromitite layers are located using a shortest path algorithm.
In order to estimate the physical orientation of any layer found, a sinusoidal
curve is fitted.
The proposed algorithms were implemented and tested on samples taken
from photographed cores. A high success rate was obtained in rock classification,
and thin planar layers were located and characterised.
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A study of failure in the rock surrounding underground excavationsCook, Neville G.W. January 1962 (has links)
A Thesis presented to the Department of Geophysics
of the University of the Witwatersrand,
Johannesburg / Violent failure of the rock surrounding under ground excavations
forms a major hazard and obstacle in deep-level mining. (Abbreviation abstract) / AC 2018
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Busca de oligoelementos em rochas vulcânicas / Search of Oligoelements in Volcanic StonesGuillaumon, Pedro Vinícius 25 August 2014 (has links)
Foram realizadas medidas de espectroscopia gama simples, de espectroscopia gama-gama em anti-coincidência e coincidência em dezessete amostras de rochas vulcânicas irradiadas com nêutrons térmicos. Foram determinadas, utilizando cálculo covariante, 33 elementos químicos (Al, As, Ba, Ca, Ce, Cl, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, Ti, U, Yb, Zn e Zr), dos quais 21 elementos traço. Foi determinado o limite máximo de detecção para o irídio em 11 amostras. Foi obtido um valor máximo de 0,7 ppb. Os resultados foram comparados com o processo astrofísico de formação da Terra. A concentração de urânio e tório variou entre 3 ppm e 9 ppm, com exceção das amostras de Kilimanjaro, que variou entre 40 ppm e 45 ppm. Abaixo da concentração de 12 ppm presentes na crosta terrestre. Espera-se concentrações menores devido a estimativas de tório e urânio através do calor emitido pela Terra. Foram determinados 10/17 lantanídeos, com destaque para a abundância de Ce em Kilimanjaro, cujos valores obtidos foram de 272 (6) ppm e 319 (11) ppm. / Single gamma ray spectroscopy, gama-gama coincidence and anticoincidence spectroscopy have been performed to study 17 volcanic rocks irradiated with neutrons. We have determined, using covariant calculations, 33 chemical elements including 21 trace elements: Al, As, Ba, Ca, Ce, Cl, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, Ti, U, Yb, Zn e Zr. We set a maximum limit of detection for iridium in 11 samples. We have determined a maximum value of 0,7 ppb. The results were associated to the astrophysical process that led to the Earth formation. Thorium and uranium abundance ranged between 3 ppm e 9 ppm, except for the samples of Kilimanjaro, which ranged from 40 ppm to 45 ppm. Less than 12 ppm, the Earth\'s Crust abundance of thorium and uranium. Using the heat emitted by Earth to estimate the abundance of them led to significant lower values. We have also determined 10/17 lanthanides, like Ce that has an abundance of 272 (6) ppm and 319 (11) ppm, in the case of Kilimanjaro\'s samples.
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Petrographic image analysis as a tool to quantify porosity and cement distributionNejedlik, John. January 2001 (has links) (PDF)
Includes bibliographical references (leaves 153-157). Petrographic image analysis proved particularly useful in determining the parameters for statistical analysis for the simple mineralogies displayed in the samples from the Hutton Sandstone. Concentrates on establishing techniques for statistical study of data collected by PIA to subdivide the framework grains from the porosity or cement.
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