This Ph.D. project aims to aquire a better understanding of sedimentological and ecological processes within the immediate vicinity of Large Igneous Province (LIP) activity and of the effects that LIP volcanism may have on the environment. The Miocene Columbia River Flood Basalt Province (CRBP) comprises an up to 4500 m thick succession of basaltic lavas intercalated with fluvio-lacustrine siliciclastic and volcaniclastic sediments. Detailed field-based studies (logging of 47 interbed sites) and the generation of geochemical (XRF, SEM, and microprobe) and palynological data provide an integrative study of characterising and modeling sedimentological and ecological processes within the lava field. The generation of a sedimentary facies scheme allowed a reconstruction of the intra-lava drainage system through time. Drainage system evolution is largely controlled by CRBP volcanism which is capable of forcing fluvial systems to the margin of the lava field during the phases of high volcanic activity, while phases of waning effusion frequencies and volumes allow the fluvial environment to migrate back into the central part of the lava field. The composition of the siliciclastic sediments suggests external source areas mainly located in the Cascade Range west and north of the CRBP. High plant diversity and late successions occurred during the early stage of CRBP evolution, and were affected by the increased deposition of ash derived from Cascade Range volcanoes and the Yellowstone hot spot during the late stage of CRBP evolution. Interbed sites distal to the volcanic source are generally colonized by late-successional plants and suggest a relationship between nutrient flux, sedimentary environment and volcanism. Palaeoclimate reconstructions based on soil chemistry and floral composition suggest that climatic changes within the CRBP reflect the global trend of the Mid-Miocene Climate Optimum. The present work allows to model sedimentological and ecological processes within the CRBP and considers the various effects that volcanic activity has on the environment. The complexity and differences in the geology and igenous evolution of individual LIPs need to be considered when applying this model to other LIPs.

The probable pollution distribution and flushing times have been calculated for the Columbia River Estuary, a coastal plain estuary. The pollution distribution was determined by the fresh water fraction and by the diffusion equation. The flushing times were calculated by the modified tidal prism method and by the fraction of fresh water, These methods are explained and discussed in the study. The widely varying river flow and resulting salt water intrusion were considered, as well as the varying semi-diurnal tidal range. These changing factors cause a complex variation in estuarine classification from well-mixed to stratified. The data used was taken principally from the U. S. Corps of Engineers current measurement program of 1959. The data show a stronger flow on the north side of the estuary during flood tide and a stronger flow on the south side during ebb tide. Due to this fact, the estuary was also treated as two separate channels in calculating the pollution distribution. The results of the various calculations for combinations of conditions are given in this study. A comparison of the different methods is also summarized. The estuary has been found to have a relatively short flushing time, even under low river flow conditions. The variation in strength of flow from the north side to the south side has been shown to produce pollution distributions not normally expected in an estuary. / Graduation date: 1965

No description available.

Graduation date: 1979

Thesis (M.S.)--Oregon State Agricultural College, 1936. / Typescript. Includes bibliographical references (leaves 124-130). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 236-246). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--University of Oregon, 2007. / Includes vita and abstract. Includes bibliographical references (p. 272-296). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 94-101). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Oregon, 2006. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 236-246). Also available for download via the World Wide Web; free to University of Oregon users.