Thesis (Ph. D.)--University of Wisconsin--Madison, 1933. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The Flange-Midway types were found to be petrographically indistinguishable from ordinary sills. The cause of the bluish colour of Flange specimens could not be definitely established. The porphyries may have been altered both by deuteric and by hydro-thermal action. Studies of zoned plagioclases indicate a magmatic origin for at least one of the sills. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The Pine, Fin, and Mex porphyry Au-Cu ± Mo systems are all located within a 10 km² area in the Toodoggone district, along the eastern margin of the Stikine terrane in British Columbia. Multiple episodes of porphyry-style mineralization are associated with these three magmatic centres. The Fin monzogranite is the oldest dated pluton in the district, with a U-Pb zircon emplacement age of 217.8 ± 0.6 Ma. A cross-cutting main-stage quartz-pyrite-chalcopyrite ± molybdenite ± sphalerite vein gives an older Re-Os molybdenite mineralization age of 221.0 ± 1.4 Ma. Hence the vein probably cross-cuts a slightly older, undated magmatic phase. Lead isotope values for sulphide minerals from main-stage veins indicate that magmatic-derived fluids interacted with country rocks and possibly other fluids. The Pine quartz monzonite (U-Pb zircon emplacement age of 197.6 ± 0.5 Ma) intrudes, alters, and locally mineralizes Toodoggone Formation Duncan Member andesite tuff (U-Pb zircon age of 200.9 ± 0.4 Ma). High-grade (0.57 g/t Au and 0.15% Cu) mineralization occurs in main-stage quartz-magnetite chalcopyrite-pyrite veins and disseminated throughout the potassic alteration zone in the Pine quartz monzonite stock. Late-stage anhydrite-pyrite ± specular hematite ± chalcopyrite, quartz-pyrite ± chalcopyrite, and pyrite ± chalcopyrite veins and related phyllic alteration cross-cut earlier veins. Propylitic alteration occurs distal to the potassic core of Pine in the Fin monzogranite and Duncan Member andesite. Limited fluid inclusion data, in combination with S and Pb isotope values for veins and host rocks, suggest that the main-stage fluid was magmatic-derived and deposited metals at 430 to 550 °C and depths of about 5.5 km. Late-stage fluids were also probably derived from the Pine quartz monzonite but interacted with Takla Group country rock prior to metal deposition. Metals were deposited at temperatures of 330 to 430 °C and depths of about 5.0 to 5.5 km. The final mineralization phase of the Pine porphyry system is temporally constrained by the emplacement of weakly mineralized syenite dykes (U-Pb zircon age of 193.8 ± 0.5 Ma). The final stage of magmatism in the Pine-Fin-Mex area is defined by the emplacement of rhyolite dykes (U-Pb zircon age of 193.6±0.4 Ma).

The Pine, Fin, and Mex porphyry Au-Cu ± Mo systems are all located within a 10 km² area in the Toodoggone district, along the eastern margin of the Stikine terrane in British Columbia. Multiple episodes of porphyry-style mineralization are associated with these three magmatic centres. The Fin monzogranite is the oldest dated pluton in the district, with a U-Pb zircon emplacement age of 217.8 ± 0.6 Ma. A cross-cutting main-stage quartz-pyrite-chalcopyrite ± molybdenite ± sphalerite vein gives an older Re-Os molybdenite mineralization age of 221.0 ± 1.4 Ma. Hence the vein probably cross-cuts a slightly older, undated magmatic phase. Lead isotope values for sulphide minerals from main-stage veins indicate that magmatic-derived fluids interacted with country rocks and possibly other fluids. The Pine quartz monzonite (U-Pb zircon emplacement age of 197.6 ± 0.5 Ma) intrudes, alters, and locally mineralizes Toodoggone Formation Duncan Member andesite tuff (U-Pb zircon age of 200.9 ± 0.4 Ma). High-grade (0.57 g/t Au and 0.15% Cu) mineralization occurs in main-stage quartz-magnetite chalcopyrite-pyrite veins and disseminated throughout the potassic alteration zone in the Pine quartz monzonite stock. Late-stage anhydrite-pyrite ± specular hematite ± chalcopyrite, quartz-pyrite ± chalcopyrite, and pyrite ± chalcopyrite veins and related phyllic alteration cross-cut earlier veins. Propylitic alteration occurs distal to the potassic core of Pine in the Fin monzogranite and Duncan Member andesite. Limited fluid inclusion data, in combination with S and Pb isotope values for veins and host rocks, suggest that the main-stage fluid was magmatic-derived and deposited metals at 430 to 550 °C and depths of about 5.5 km. Late-stage fluids were also probably derived from the Pine quartz monzonite but interacted with Takla Group country rock prior to metal deposition. Metals were deposited at temperatures of 330 to 430 °C and depths of about 5.0 to 5.5 km. The final mineralization phase of the Pine porphyry system is temporally constrained by the emplacement of weakly mineralized syenite dykes (U-Pb zircon age of 193.8 ± 0.5 Ma). The final stage of magmatism in the Pine-Fin-Mex area is defined by the emplacement of rhyolite dykes (U-Pb zircon age of 193.6±0.4 Ma).

Thesis (Ph.D.) - James Cook University, 2005. / Appendix A (pdf version of Chapter 1) is contained on CD-ROM. Typescript (photocopy) Includes bibliographical references.

Thesis (doctoral)--Universität Marburg, 1897. / Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / One folded map in pocket. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 71-74).

The Pine, Fin, and Mex porphyry Au-Cu ± Mo systems are all located within a 10 km² area in the Toodoggone district, along the eastern margin of the Stikine terrane in British Columbia. Multiple episodes of porphyry-style mineralization are associated with these three magmatic centres. The Fin monzogranite is the oldest dated pluton in the district, with a U-Pb zircon emplacement age of 217.8 ± 0.6 Ma. A cross-cutting main-stage quartz-pyrite-chalcopyrite ± molybdenite ± sphalerite vein gives an older Re-Os molybdenite mineralization age of 221.0 ± 1.4 Ma. Hence the vein probably cross-cuts a slightly older, undated magmatic phase. Lead isotope values for sulphide minerals from main-stage veins indicate that magmatic-derived fluids interacted with country rocks and possibly other fluids. The Pine quartz monzonite (U-Pb zircon emplacement age of 197.6 ± 0.5 Ma) intrudes, alters, and locally mineralizes Toodoggone Formation Duncan Member andesite tuff (U-Pb zircon age of 200.9 ± 0.4 Ma). High-grade (0.57 g/t Au and 0.15% Cu) mineralization occurs in main-stage quartz-magnetite chalcopyrite-pyrite veins and disseminated throughout the potassic alteration zone in the Pine quartz monzonite stock. Late-stage anhydrite-pyrite ± specular hematite ± chalcopyrite, quartz-pyrite ± chalcopyrite, and pyrite ± chalcopyrite veins and related phyllic alteration cross-cut earlier veins. Propylitic alteration occurs distal to the potassic core of Pine in the Fin monzogranite and Duncan Member andesite. Limited fluid inclusion data, in combination with S and Pb isotope values for veins and host rocks, suggest that the main-stage fluid was magmatic-derived and deposited metals at 430 to 550 °C and depths of about 5.5 km. Late-stage fluids were also probably derived from the Pine quartz monzonite but interacted with Takla Group country rock prior to metal deposition. Metals were deposited at temperatures of 330 to 430 °C and depths of about 5.0 to 5.5 km. The final mineralization phase of the Pine porphyry system is temporally constrained by the emplacement of weakly mineralized syenite dykes (U-Pb zircon age of 193.8 ± 0.5 Ma). The final stage of magmatism in the Pine-Fin-Mex area is defined by the emplacement of rhyolite dykes (U-Pb zircon age of 193.6±0.4 Ma). / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Mo became very important in the last century, because of its sophisticated properties and its use in the new technology of alloys . Porphyry systems (porphyry Cu-Mo and Mo) contribute a significant proportion (90 - 95 per cent) to the Mo world's production. This type of deposit is associated mainly with Phanerozoic orogenic belts. Above 87per cent of the world resources are in the American Circumpacific belts , both Andean and Cordilleran . Ore grade in porphyry Cu-Mo range from 0,005 to 0,04per cent Mo, whereas in porphyry Mo grades range from 0,08 to 0,75per cent Mo . These deposits are associated with a magmatism which shows an evolution from calcic in island arcs, to calc-alkaline in magmatic back arcs, with an increase of the Mo content in the same direction. Porphyry Mo deposits display several features in common with porphyry Cu deposits. hydrothermal Similarities include nature of host alteration patterns and distribution of rock intrusives, ore minerals. An interesting difference is found in the Re contents of the molybdenite mineral. This element is higher in the molybdenites of porphyry Cu, than in those of the porphyry Mo. The ore genesis process begins involves partial melting, within enriched zones of the upper mantle and magma differentation, liquid state thermogravitational diffusion, magma convection and boiling. These processes progressively concentrate Mo in the fluids, which are released at some stage, into sulphidic hydrothermal systems, under complex geologictectonic conditions involving fracturing, brecciation and hydrothermal alteration. Major concentrations of the ore mineral are always associated with potassic alteration, and with late magmatic-early hydrothermal stages (Chilean and Western North American porphyries). Geological mapping and a close understanding of alteration and mineralization patterns, and lithogeochemistry are important tools for the exploration of porphyry Mo deposits. Geochemical prospecting, using soils, vegetation and water as sampling media, and regional aeromagnetic, gravity surveys, aerial photography and remote sensing, are us.

Thesis (M.S.)--University of Puerto Rico, Mayagüez Campus, 2005. / Tables. Printout. Includes bibliographical references (leaves 130-135).