Late Permian kuroko-type mineralization in the Bully Hill area of the East Shasta district formed along two horizons within the Bully Hill rhyolite. In the Bully Hill, Rising Star, and Copper city mine areas, syngenetic mineralization is underlain by alteration zones characterized by addition of SiO₂ and K₂O, loss of NaCO, CaO, and Fe₂O₃* , and the assemblage quartz + sericite + pyrite. Quartz precipitation in the upper portion of the zones led to cyclic sealing of fluid flow, rupturing of the seal, quartz supers aturation, focused fluid discharge, and formation of sulfide mounds on the seafloor. Syngenetic mineralization occurred in several stages: (1) deposition of fine-grained banded sulfides and gangue; (2a) recrystallization of Stage 1 minerals, and void-filling by pyrite + weakly chalcopyrite-diseased sphalerite ± barite; (2b) deposition of coarsely-crystalline pyrite + heavily chalcopyrite-diseased sphalerite; (3a) void-filling and replacement by galena + chalcopyrite + tetrahedrite-tennantite; (3b) replacement by chalcopyrite; and (4) replacement by barite. ΣSO₄⁼ and H₂S contents of hydrothermal fluids decreased from Stages 2a to 3a. δ³⁴S values of sulfides increased successively from Stages 1 (-15.8 per mil) to 3a (3.0 per mil), reflecting variable inputs of biogenic sulfur and deep-seated fluid evolution. δ³⁴S values of syngenetic barites range from 12.4 to 22.5 per mil, reflecting cold seawater and hydrothermal sulfur sources, respectively. δ³⁴S values of epigenetic pyrite and barite within the alteration zones range from -0.7 to 2.7 per mil and 12.4 to 24.1 per mil, respectively. Primary and pseudosecondary fluid inclusions in epigenetic minerals have filling temperatures of 240 to 260 °C and salinities of 3 to 12.3 equivalent weight percent NaCl. Lower limits of fluid salinities and δ³⁴S values of barite indicate that seawater was a primary component of the hydrothermal fluid, and that seawater also mixed with discharging fluids on the seafloor. High fluid salinities, the lack of a silica source, and the close link of magmatism with mineralization indicate that magmatic fluids may have been an important component of the hydrothermal fluids.

No description available.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 174-191). Also available on the World Wide Web.

Thesis (M.S.)--Humboldt State University, 2008. / Includes bibliographical references (leaves 66-69). Also available via Humboldt Digital Scholar.

The purpose of this study was to evaluate a period in the history of the region surrounding Mount Shasta, a sentinel on the surface of the earth and in the minds of ancient as well as modern man. The study presents the area's geologic history, its pre-history and discovery by the white man in order to provide the reader with an understanding of the later exploration and early settlement of the region. The emergence of the U.S. Forest Service and the creation of Shasta Forest as well as the evolution of Federal regulatory policy and control is presented along with a discussion of the area's transition and recent wilderness legislation. It is the writer's hope that this information might be utilized by others who are concerned with the preservation of the Shasta Peak Wilderness Area.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 58-60). Also available online.

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 90-96). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2006. / Title from metadata title field (viewed Nov. 13, 2006). Includes bibliographical references (p. 90-96).

Aquatic ecosystems continue to be increasingly affected by climate warming. For salmonids in the Pacific Northwest of North America, increasing temperatures pose tighter thermal constraints on their habitat use as well as aspects of their individual performance, such as disease resistance. This thesis examines the effect of temperature on the phenology of the Ceratomyxa shasta life cycle, the effect of thermal refugia on disease risk in juvenile salmonids in the Klamath River, CA, and the spatial and temporal distribution of C. shasta in the Willamette River, OR. We developed a biological model that predicts an acceleration of the C. shasta life cycle development due to climate shifts in the Klamath River, resulting in more generations per year and earlier seasonal parasite occurrence. We showed that in early summer the Beaver Creek-Klamath River confluence provides juvenile Chinook and coho salmon an area of lower parasite doses and cooler temperatures than the main stem, thus lessening disease risk. By accelerating the development of C. shasta in its hosts, increasing temperatures will result in earlier parasite transmission to juvenile salmonids and a longer season of infectivity. These fish may find disease refuge at cold tributary inflows to the main stem of the Klamath River in early summer, further adding to the benefit of these important thermal habitats. To determine if similar disease patterns occur in other rivers with the parasite, we described spatial and temporal occurrence of C. shasta in the Willamette River. By collecting weekly water sampling at four sites over 28 months we characterize seasonal and annual differences of parasite abundance, which varies with weekly temperature. We also collected samples along the length of the main stem and its tributaries and identified spatial differences in C. shasta spore densities. Identification of spatial and temporal variation of C. shasta in the Willamette River provides a foundation for understanding future patterns of disease occurrence in this river where conservation of anadromous fisheries is also of concern. This thesis identifies likely responses of C. shasta to climate warming in the Klamath River, with useful application to other rivers in the Pacific Northwest. / Graduation date: 2013

Thesis (M.S.)--Humboldt State University, 2008. / Includes bibliographical references (leaves 53-55). Also available via Humboldt Digital Scholar.