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A study of calcareous nannofossils from the Maastrichtian-Early Eocene from Egypt has resulted in the recognition of four Maastrichtian and seven Early Tertiary biostratigraphic zones. These nannoplankton zones are based upon local ranges and compared with the zones proposed by Martini (1971), Sissingh (1977), Verbeek (1977) and Romein (1979). A new zone, the Fasciculithus ragaae Zone is described and the E1lipsolithus macellus Zone and the Fasciculithus tympaniformis Zone are emended. Study of the vertical ranges of the species provided many markers (including the zonal markers) with distinctive first and/or last occurrence levels. The uppermost Maastrichtian and Lower Danian are missing in the study sections. There is no change in the lithology at the Cretaceous-Tertiary boundary as observed in the Esh Mellaha area, but biostratigraphic evidence shows that there is a time gap and the boundary missing. This boundary is, however, marked by a conglomerate band at Gebel Urn El Ghanayem, a thin bed of black non-calcareous shale at Gebel Duwi and a change in the lithology from chalky limestone (upper part of Sudr Chalk Formation) of Maastrichtian age to shale (lower part of Esna Shale Formation) of Early Palaeocene age at Wadi Tarfa. No continuous Cretaceous-Tertiary boundary sequence was analysed. The palaeoenvironment during the Maastrichtian-Early Eocene according to the nannofossil assemblages, was a warm open marine inner to outer shelf, although the absence of late Maastrichtian and early Danian age sediments limits observation and comment. One hundred and sixty five species have been identified. Descriptions, remarks and figures as well as schematic drawings of many species are presented. A new family RHOMBOASTERACEAE, a new genus Diadochiastozygus, five new species Fasciculithus ragaae, F. gelelii, Discoaster atefii, D. duwiensis and D. amrii are described. New combinations for Bomolithus megastypus, B. cantabriae, Diadochiastozygus imbriei, D. saepes, D. eosaepes, Tranolithus tarboulensis, Vekshinella dorfii and V. compacta are proposed. The evolution of some Cretaceous and Early Tertiary nannofloral groups is discussed and a link between the Bomolithus and Discoaster groups proposed.

The use of shells from terrestrial and freshwater molluscs for radiocarbon dating has in the past been viewed with scepticism or even dismissed entirely because the results are prone to distortion from post-depositional diagenesis, or the incorporation of material with a low 14C/12C ratio whilst the mollusc was alive, or both. The thesis attempts to discuss how the relative importance of the two factors can be assessed and the corresponding ages corrected accordingly. Diagenesis was studied by comparing the structure and chemical composition of 39 species of British molluscs from modern specimens with those of fossil samples. Three main effects of diagenesis were studied using light and scanning electron microscopy, mass spectrometry and atomic absorption spectroscopy: the transformation of aragonite to calcite, a reduction in the standard deviation associated with the distribution of major ion concentrations within a shell population, and an enrichment in the lighter isotopes of carbon and oxygen. Only the transformation of mineralogy proved to be sufficiently sensitive to detect diagenetic material present at levels of 1-27%. The effects of diet and ambient carbon dioxide were studied by chemical analysis and mass spectrometry. Differences in stable isotope ratio values between micro-environments were found to be significantly greater than those between and within species. The established relationship between 13C, 14C and the environment can be used to identify shells in which the apparent age effect will be at a minimum. Comparison of 14C dates for charcoal and untreated shell samples showed that the above sources of error led to discrepancies of as much as 1500 years in the shell dates. Seven samples selected and pretreated in accordance with the procedures proposed in this thesis gave ages within two standard deviations of the values accepted for the deposit in question, and four samples gave ages which were being statistically identical with the accepted values. In addition, the screening tests permitted samples destined to give erroneous ages to be identified from the outset.

Thesis (Ph. D.)--University of Washington, 1993. / Vita. Includes bibliographical references (leaves [191]-200).

Thesis (Masters)--California Institute of Technology, 1951. / Title from home page (viewed 04/27/2010). Includes bibliographical references.

Thesis (Masters)--California Institute of Technology, 1932. / Title from home page (viewed 04/21/10). Includes bibliographical references.

Thesis (Masters)--California Institute of Technology, 1932. / Advisor names found in the Acknowledgments pages of the thesis. Title from home page (viewed 04/20/10). Includes bibliographical references.

Thesis (Masters)--California Institute of Technology, 1932. / Advisor names found in the Acknowledgments pages of the thesis. Title from home page (viewed 04/20/10). Includes bibliographical references.

No description available.