The purpose of this paper is to give a brief description of the stratigraphy of the Lower and Middle Ordovician formations of the St. Lawrence Lowlands together with a short summary of the historical geology of the time. The basis for the paper is the literature on the subject, as the author's personal investigation has been restricted to one summer's work in a small section of the Lowlands. For the purpose of this description, the limits of the area are first defined and the region is then subdivided into three parts. There follows a description of the Beekmantown formation in which the problem of the Potsdam and Nepean sandstones is discussed. Afterwards, the historical geology of the epoch is given in resume. The Chazy formations are in turn examined, and the historical geology of the period is supplied. The more complex problem of the Black River, Trenton, and Utica stratigraphy is then analyzed. Changes in facies and thicknesses of contemporaneous formations in different parts of the Lowlands are studied with particular reference to the work of Raymond, Kay, Okulitch, Clark, and Wilson. An attempt to correlate these formations is made, but, owing to the complexity of the problem and the small amount of information available on many areas, the picture is left incomplete. The historical geology of this third marine invasion covering the St. Lawrence Lowlands from Black River to Utica time, is reviewed. The bibliography does not pretend to be exhaustive. It contains works on the stratigraphy of the Lower and Middle Ordovician Period and some works dealing with the palaeontology have also been included as a useful complement to the stratigraphy. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The pre-Jurassic tectonic events of the area controlled the nature of sedimentation. These tectonic events were the result of movements of the members of the tectonic framework. The nature of the tectonic framework was established during Beltian sedimentation and was inherited by the Paleozoic era. During the Paleozoic era, the movements of various members of the tectonic framework resulted in four sequences or cycles of sedimentation. Tectonism and its control upon sedimentation from Beltian to pre-Jurassic time is shown as Beltian sedimentation and the succeeding sedimentary cycles are discussed. Type localities are defined for the Beltian and Paleozoic strata of each sequence as they occur in the area. Problems of age determination for the stratigraphic units are discussed and the correlation of these units within and beyond the are presented. These correlations show the relationship of the stratigraphic nomenclature of Montana and Alberta. Since the thesis is mainly limited to published information, it indicates the present status of published geological thought in the area. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

No abstract included. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Data of good quality is necessary to further the study of rock lead isotopic interpretations. An internal standard (double-spike) was employed to correct for fractionation accompanying the single filament analyses, and lead isotope ratios with a standard deviation of 0.15% were obtained. Lead sulphide mounted on tantalum was employed for the lead analyses. Discrimination in the analyses using tantalum filaments was consistent with the theoretical fractionation laws. This was not found to be the case for rhenium. Lead and uranium analyses from the Vogt-Hobbs area near Lake Timagami, Ontario and from the Rice Lake-Beresford Lake Area, Manitoba revealed variations from a simple two stage model that could not be accounted for by experimental error. Interpretation of the data yields a three stage history for both of these regions, marked by major events at approximately 3400 and 2600 my ago. This earlier crustal history is supported by ore lead data from the vicinity. Both of the suites have a lower average value of (U238/Pb204) for the second stage, of their three stage history, than is characteristic of the source of single stage leads. Variations from closed system behaviour for the Ontario samples is attributed to lead remobilization at the time of the Grenville event. Remobilization of the lead tends to mask the 2600 my old event. The Vogt-Hobbs area is characterized by more acidic igneous rocks and more radiogenic lead than the Rice Lake-Beresford Lake area. These differences are thought to represent the environment 2600 my ago or earlier. The Manitouwadge lead analysed by Ostic resembles the lead - 2600 my ago in the Rice Lake-Beresford Lake rock samples. The Rice Lake-Beresford Lake rock samples are shown according to the interpretation presented, to have had a crustal history prior to 2600 my ago. This lends weight to arguments that exclude Manitouwadge from the class of single stage leads used in calculations of the age of the earth. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

[No abstract available] / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Bibliography: leaves 221-229. Also available online.

Thesis (Ph.D.) -- Macquarie University, School of Earth Sciences, 1996. / "September, 1995" Bibliography: leaves 171-183.

Thesis (M.A.)--Ohio State University, 1915. / Available online via OhioLINK's ETD Center.

Inaug.-diss.--Basel. / "Separatabdruck aus: Eclogae geologicae Helvetiae, vol. 29, no. 1, 1936." Curriculum vitae. "Literatur": p. 143-149.