Thesis (M.S.)--Oregon State University. / Part of illustrative matter in pocket. Includes bibliographical references (leaves 98-103). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 257-265). Available also in a digital version from Dissertation Abstracts.

This project studies the relation between the amount of sediment deposited in the Nile Submarine Cone (NSC) and the influence exerted by external controls such as climate change. A detailed calculation of sediment volumes was performed as well as a detailed estimation between intervals in order to assess sedimentation rates and dry mass per Ma for the NSC from the Late Oligocene to Recent. In contrast to previous studies, this project presents for the first time detailed calculations for ten intervals from Late Oligocene to Re- cent, including calculations for Pre-Messinian deposits since they also play an important role in the evolution of the NSC and in the history of erosion and deposition processes in the Nile province. The results of this project evidenced a connection between climate change and the amount of sediment carried by rivers as well as its final fate. Sedimenta- tion rate values obtained for each interval showed an increase in sediment supply during the Late Pliocene-Early Pleistocene, coincident with the i) final uplift of the Ethiopian and Somalian plateaus, ii) the drop in temperatures that took in the northern hemisphere as a consequence of the growth of the ice sheets, and iii) the increase in rainfall in the Ethiopian Highlands as a consequence of the African and Indian Monsoon that produced sapropel deposits and eroded sediments in north-eastern Africa. Pre-Messinian intervals showed low sedimentation rates values compared to Post-Messinian associated probably with an elevated evapo-transpiration cycle reducing the rainfall in the Ethiopian Highlands, des- pite the humid conditions that were present during certain ages (e.g. Zeit Wet Phase Late Miocene).

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Palynological and stratigraphic investigations have been conducted on sediment cores for three sites in Lothian Region, Scotland: Balgone House, Broxmouth and Corstorphine. All phases of the Lateglacial period, as far as they are manifested in the Lothians at the sites studied, have been investigated with particular reference to the Younger Dryas, the main Interstadial, or Allerod, and also the evidence for the colder conditions that preceded it which are presumed to represent Older Dryas-type vegetation. Further light has been cast on the development of the Postglacial broad - leaved forests. The Cambridge computer program POLLDATA MKV was used to perform the necessary calculations and controlled a graph plotter to generate pollen diagrams. A series of subroutines is described that translated the calls to the Cambridge graphics subroutine library. This may serve as a model for other installations. Objective numerical zonation methods are applied to the pollen data. These methods are used not only to zone the pollen series but also to aid in the generation of hypotheses regarding vegetation changes. Chemical analyses of the sediments from Balgone House were undertaken. The results obtained are at variance with those from published work and it is proposed that the reason is that the chemical pre-treatment of samples employed locally may be less efficient in leaching the cations from the mineral fraction.

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