Studies in Organic Geochemistry

Maxwell, James Rankin (1967) Studies in Organic Geochemistry. PhD thesis, University of Glasgow.

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Organic geochemistry is the study of organic matter in geological situations, including contemporary environments. One facet of the subject is the isolation and identification of organic compounds from fossils and sediments. Correlations are then sought between such compounds and the biological compounds present in contemporary organisms, bearing in mind the chemical changes which could have taken place. in this thesis an attempt has been made to relate chemically a living alga, Botryococcus braunii , a derived rubbery deposit called Cocrengite and Torbanite which is a sediment 300 million years in age. The thesis can be divided into six parts, five of which are concerned with organic geochemistry. The Introduction reviews the more significant contributions to organic geochemistry and describes the types of compounds found in sediments, with special reference to alkanes. Some of the various facets of the subject and the possible derivations of geological isoprenoid alkanes ere also discussed. Section I is concerned with the alkanes present in two samples of a young sediment (ca. 30 x 10e6 yrs.) from N. W. Bohemia, Czechoslovakia. The distributions of the normal alkanes are reminiscent of those of the normal alkanes of the surface waxes of most contemporary plants. Furthermore the predominance of triterpene hydrocarbons in the branched-cyclic aIkam fraction is in accordance with the fact that the plant species identified in the sediment are mainly angiosperms. The diterpene hydrocarbon fichtelite was identified in one of the samples. Section II deals with the alkanes of a number of samples from the Scottish Carboniferous Formation (ca. 300 x 10e6 yrs.). The normal alkanes of these samples have smooth distributions in contrast to those found for the young sediment examined (Section I). A number of acyclic isoprenoid hydrocarbons were identified, indicating that the samples have a biological origin. Triterpene hydrocarbons were isolated from one of the samples, viz. the Westwood Shale and their occurrence reflects the difference in source material between this and a closely related sediment called Torbanite. The Westwood Shale is the oldest geological sample from which triterpanes have been isolated in a pure state. Section III describes the hydrocarbons of a rubbery deposit called Coorongite (ca. 40 yrs.) which is the presumed precursor of Torbanite. The unusual hydrocarbon distributions found in Coorongite are thought by the author to be the result of bacterial activity. Three acyclic isopronoid hydrocarbons were identified in the sample examined. Section IV deals with the hydrocarbons of a living alga, Botryococcus braunii, which gives rise to Coorongite. No saturated hydrocarbons were detected in the alga and the hydrocarbon fraction was found to consist almost entirely of two novel hydrocarbons. Approaches to the structural elucidation of these hydrocarbons are described. The Appendix is concerned with the interactions which can take place between a nitro-group and a side chain in orthosubstituted nitrobenzenes . The types of interaction which have been observed are reviewed and two new examples are descried. A mass spectral method for the identification of the N-oxide function in aromatic N-oxides is discussed.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Geochemistry
Date of Award: 1967
Depositing User: Enlighten Team
Unique ID: glathesis:1967-78433
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 28 Feb 2020 12:09
Last Modified: 28 Feb 2020 12:09

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