Thesis (Ph. D.)--Ohio State University, 1968. / Includes vita. Includes bibliographical references (leaves 138-145). Available online via OhioLINK's ETD Center.

No description available.

No description available.

Thesis (Ph.D.) -- University of Adelaide, Dept. of Economic Geology, 1974. / Original drawings in box.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1928. / The entire thesis text is included in file. Typescript. Can find no evidence of student graduating with a Master's Degree in the "1874-1999 MSM-UMR Alumni Directory or in any of the annual catalogs. Title from title screen of thesis/dissertation PDF file (viewed Sept. 14, 2009). Includes bibliographical references (p. 22).

No description available.

The Coed-y-Brenin system is a diorite-hosted porphyry copper deposit of early Ordovician age (Tremadoc) situated on the south eastern side of the Harlech Dome: a thick sequence of Cambrian and Ordovician sediments and volcaniclastics that were subject to greenschist facies metamorphism during the Caledonian Orogeny. The copper mineralization occurs as disseminations, coatings on hairline fractures and in late-stage quartz-sulphide-calcite veinlets. Pyrite and chalcopyrite are the main opaque phases but sulphosalts, tellurides and electrum are also present. The copper mineralization is largely confined to the diorite and micro-tonalite dykes and sills associated with the Rhobell Fawr Volcanic centre. This study has shown that epithermal style precious-metal mineralization is also developed in the Coed-y-Brenin area in the shales and siltstones of the Maentwrog and Ffestiniog Flags Formations. It is characterised by pyritization, sericitization and silicification. The gold and silver occur as electrum in fractures and also as tellurides in late stage quartz-pyrite veins. Both styles of mineralization share a close spatial association and are characterised by propylitic and phyllic alteration. Argillic and potassic assemblages are not developed. Geochemical analysis of mineralized and unmineralized material has shown that the diorite-hosted mineralization is enriched in Cu, Au and Ag and depleted in Zn while the epithermal mineralization displays enrichments in Au, Ag, As, Sb and the base metals. Rb:Sr ratios increase with increasing alteration in both styles of mineralization. Sulphur isotope studies have shown that both styles of mineralization have a common, probably magmatic, sulphur source. Fluid inclusion data and 0 and H isotope studies indicate that following magma emplacement and development of the porphyry copper mineralization a low temperature-low salinity meteoric hydrothermal system was established. Fluid inclusion data and 0 and H isotope studies indicate that following magma emplacement and development of the porphyry copper mineralization a low temperature-low salinity meteoric hydrothermal system was established. This was responsible for the late-stage quartzsulphide-calcite veins in the diorites and for all the sediment-hosted mineralization. The association between epithennal and porphyry deposits has become apparent in recent years but the Coed-y-Brenin system is unusual due to its Lower Palaeozoic age and because both styles of mineralization are developed at the same structural level. This study of the Coed-y-Brenin porphyry system demonstrates the potential for the development and preservation of epithermal mineralization in porphyry systems and also in older orogenic belts.

<p> The short term (5000 hours) stability of illite and montmorillonite in sea water was studied by suspending 5.00 gm. aliquots of A.P.I. reference clays Montmorillonite # 25b and Illite # 35 in 500 ml. of artificial sea water (tradename "Instant Ocean") . After 5000 hours, in the montmorillonite samples, Ca and Si concentrations had increased (0.490 mmoles/l and 0.289 mmoles/l respectively), the cation exchange capacity had decreased (104.36 meq/100 gms. to 81.42 meq/100 gms.), the pH had decreased (8.40 to 7.94) but no major mineralogical change was observed. After 5000 hours, in the illite samples, Si concentration had increased (0.045 mmoles/l), the cation exchange capacity remained the same, the pH increased (7.22 to 7.60) and no major mineralogical change was observed. The release of Ca in the illite samples was complicated by the dissolution of calcite and significant changes in concentration of other cations (Na, K, Mg) were not observed.</p> <p> The data for Si, cation exchange and exchangeable cations are compared to that of Lewis (1950), Whitehouse and McCarter (1956), Carrol and Starkey (1958), MacKenzie et al (1965) (1967) and Russell (1970), a model developed by Houston (1972) is used to explain the Ca and Si data for the montmorillonite samples, and the implications of the apparent stability of these minerals to the case for authigenic clay formation from detrital material are discussed.</p> / Thesis / Bachelor of Science (BSc)

No description available.

No description available.