Joseph MacGillivray

B. Sc. Honours Thesis

The petrology Of Some Lherzolite Nodules From Lesotho And South Africa

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The suite of 18 lhezolite nodules from Lesotho and South Africa were studied by microprobe analysis of their constituent minerals, and by point counting. The nodules were plotted on MacGergor's (1967) pressure-temperature diagram for the various lhezolite facies. Relative depths of formation were aquired from the plot as well as a Cretaceous geotherm. The nodule composition, modal percentages, oxide weight percentages of olivine, garnet, enstatite, and dioside, and mineral composition were plotted against depth. With the possible exception of the pyrope content of the garnets, no systematic variation occurred, either with increasing depth in the upper mantle or between the South African nodules or those from Lesotho.

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Pages: 90
Supervisor: D. Barrie Clarke