No description available.

No description available.

No description available.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Extrusive carbonatites are rare igneous rocks with just 37 known localities. The majority are calciocarbonatites, the principal exception being those of the active volcano, Oldoinyo Lengai, which are strongly alkaline. Unresolved questions concerning extrusive carbonatites include: 1. Why are extrusive carbonatites at Lengai chemically different from all others? 2. Could the extrusive calciocarbonatites originally have had alkaline compositions? In order to address these questions extrusive carbonatites from both Lengai and the adjacent volcano, Kerimasi, were collected and compared. A compilation of all the available data on known extrusive carbonatites is also presented. The major results documented in this thesis are: 1. Alkali carbonatites from Oldoinyo Lengai erupted in 1993 contain petrographic evidence for an origin by liquid immiscibility from a highly fractionated peralkaline silicate melt (wollastonite nephelinite). 2. The suite of silicate rocks at Kerimasi are derived from a primary olivine nephelinite by fractional crystallisation and cumulus processes. 3. Extrusive carbonatites at Kerimasi are not genetically related to the silicate suite. By contrast intrusive sovites also present, originated by liquid immiscibility from a primitive silicate magma, equivalent to a melilite, nephelinite, at low pressure. 4. Extrusive calciocarbonatites from Kerimasi were erupted directly from the mantle. They contain phenocrysts (previously interpreted as pseudomorphs after alkali carbonate) which are now thought to have been dolomite containing calcite exsolution lamellae. 5. Of the 35 other extrusive carbonatite occurrences, none show any petrographic or geochemical evidence of having originally being alkaline. Therefore extrusive carbonatites from Oldoinyo Lengai are thought to be unique. 6. Of the 37 extrusive carbonatites, 50% are associated with melilitites or melilitebearing rocks, 27% are associated with nephelinites and the remaining 23% were erupted with no associated silicate magmas.

Thesis (M.S.)--Georgia State University, 2008. / Title from file title page. Timothy E. LaTour, committee chair; Hassan A. Babaie, Eirik J. Krogstad, William J. Fritz, committee members. Electronic text (111 p. : ill. (some col.), maps (some col.)) : digital, PDF file. Description based on contents viewed Aug. 20, 2008. Includes bibliographical references (p. 100-104).

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1912. / Bachelor of Science degree in Metallurgical Engineering earned in 1912, determined from "1874-1999 MSM-UMR Alumni Directory". The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed March 19, 2009)

Thesis (M.S.)--Ohio State University. / Bibliography: leaves 104-112. Available online via OhioLINK's ETD Center

Thesis (M.S.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 25, 2007) Includes bibliographical references.

This research aims to better understand drainage systems during mid to late Large Igneous Province (LIP) formation. A multidisciplinary study was conducted on the Lewiston Basin in the Columbia River Flood Basalt Province and the Skye Lava Field in the North Atlantic Igneous Province. A general model for drainage systems in LIPs was developed with three stages. In the early-LIP stage, the volcanic and drainage systems are confined to small basins, but as the volumetric eruption rate increases the regional drainage system is forced to the edge of the lava field. During the mid-LIP stage, the eruption rate decreases and the drainage system moves into the lava field, depositing channel sediments in the lowest parts of province while finer sediments or palaeosols develop in topographically higher areas. In the Skye Lava Field the drainage system was dominated by the uplift of the Rum Central Igneous Complex and included the incision of shallow valleys, whereas in the Lewiston Basin the most important effect was the structural control on basin topography. During the lateLIP stage, topographically high areas experience significant incision into the lava field which are filled by intracanyon flows (thick canyon-filling lava flows). These intracanyon flows may compartmentalise potential reservoirs deposited between earlier lava flows. Siliciclastic sand bodies were observed up to 12 m thick and 850 m across with minor exposure gaps, and were correlated across up to 15 km. The palynofloras associated with a number of palaeoenvironments in each province were identified the effects of other controls on the palaeoecology such as moisture availability, ashfall and substrate were established. The changes in the paJaeoclimate of the Lewiston Basin were studied using palaeosol geochemistry and palynology.