Thesis (Ph. D.)--University of Chicago, Dept. of History, August 2001. / Includes bibliographical references. Also available on the Internet.

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This thesis reports the results of a mineralogical and geochemical study of pans situated in the Northern Cape Province with special emphasis on the clay minerals. From east to west the depth and size of the pans increase and associated with this increased maturity the abundance of salt (halite and thenardite) and the quantity of green sediment are also enhanced. Chemically the sediments are dominated by SiO2 that also dilutes Fe2O3, K2O, Na2O, Al2O3 and MgO (when associated with dolomite) concentrations. Authigenic calcite, dolomite, analcime and loughlinite (Na-sepiolite) occur in some of the pans to the west and FTIR spectrometry indicates that all the pans host glauconite and/or celadonite. However, smectite, illite/smectite interstratification, kaolinite and/or chlorite and loughlinite only occur in some pans. The glauconite and/or celadonite does not occur as discrete mineral grains, but forms part of the fine-grained matrix common to all of the pans and no evidence of any precursor minerals were observed. The pan environment appears to present a closed, saline setting that is conducive for the direct precipitation of a mica with a chemical composition between that of glauconite and celadonite. The influence of the water-table on the formation of the glauconite and/or celadonite appears to be significant, as the highest abundance of salt is invariably associated with the position in the profile where the sediment appears to reach its most intense green colour. In the case of Koi Pan, the celadonite component of the solid solution seems to increase as the green colour intensifies. Loughlinite in Koi Pan and Brak Pan sediments also appear to be authigenic and it is suggested that it forms after precipitation of low Mg calcite that leads to Mg enrichment of the system and consequent sepiolite formation associated with minor dolomite. Thermoluminescence ages obtained from the Koi Pan sediment range between 37ka and 48ka before present at a depth of ~120cm below the surface, while for Brak Pan, at roughly the same depth, an age of between 110ka and older than 150ka before present was obtained. This may suggest different sedimentation rates in the pans or much younger ages and thus faster formation of glauconite and/or celadonite in Koi Pan since it is suggested that the mineral is authigenic. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

Microbial mats exist in freshwater pools atop the Ward Hunt and Markham ice shelves in the Canadian high Arctic. In this study, culture-dependent and culture-independent techniques were used to describe the microbial diversity and activity of these mat communities.Bacterial and archaeal 16S rRNA gene clone libraries were constructed from Markham and Ward Hunt mat samples. Bacterial libraries from both mats had high diversity, though the Markham library appeared more diverse than the Ward Hunt library. Over 95% of sequences in both bacterial libraries, and all isolates from both mats, grouped within the phyla Bacteroidetes, Proteobacteria, and Actinobacteria. Archaeal diversity appeared low in both mats. Only one phylotype, potentially representing a novel Euryarchaeota, was observed in both archaeal libraries. Populations in both communities showed activity at subzero temperatures, with growth of isolates at -5°C and detectable metabolic activity at -10°C, measured by radiorespiration assays of mat microcosms.

Note: / ln May 1962 the McGill University Savanna Research Project wasestablished and has been conducted since that date in the Department ofGeography p McGill University and in the savannas of the Rupununi Di strict pBritish Guiana and the Territorio do Rio Brancop Brazi!.It is generally recognised that although a very wide range of theoryhas been propounded to explain the nature and origin of savannas p no onehas yet brought forward a single convincing viewpoint which has met withuniversal acceptance. One reason for this is that the majority of theoriesextant are based upon inadequate fie ld data with almost a total lack ofexperimental evidence. The McGill Univers ity Sa vanna Research Projectwas set up for the purpose of initiating an experimental and observati onalfield programme which it was hoped would shed light upon the ecologicalrelations of the savanna p and would ultimately enable an explanation to bemade of the nature and distribution of the savanna vegetation of the region .

Bibliography: leaves 186-210. / v, 242 leaves, [19] leaves of plates : ill. (chiefly col.), map ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The Granites gold deposits of The Granites-Tanami Inlier are the principal interest of the thesis. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1998

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