The mineralogy, petrology and petrogenesis of a representative suite of late Archean syenitic intrusions emplaced along the Porcupine-Destor fault zone near Matheson, Ontario in the southern Abitibi greenstone belt are studied using a combined approach involving field work, petrography, mineral chemistry and, major and trace element geochemistry. Members of the Matheson suite are from east to west: Iris, Garrison, Emens, Ludgate and Pangea intrusions. The Iris, Emens, Ludgate and Pangea intrusions are mostly composed of syenitic rocks with compositions ranging from alkali-feldspar quartz-syenite to melasyenite. Textures range from equigranular to porphyritic. Iris and Pangea intrusions also contain related mafic rocks. The Garrison intrusion is composed of hornblende quartz-monzonite. All intrusions but one have hypersolvus feldspar assemblages; the exception being Garrison intrusion, which displays a subsolvus feldspar assemblage. The occurrence of late aegirine-augite, magnesioriebeckite and widespread albite replacement, especially in rocks from Ludgate and Iris intrusions, indicates that late or post-magmatic sodium-rich fluids variably affected the rocks.
Two magmatic series were identified based on silica-saturation properties and alkali-contents. (Abstract shortened by UMI.)
| Identifer | oai:union.ndltd.org:uottawa.ca/oai:ruor.uottawa.ca:10393/26423 |
| Date | January 2003 |
| Creators | Pigeon, Luc |
| Contributors | Lalonde, Andre E., |
| Publisher | University of Ottawa (Canada) |
| Source Sets | Université d’Ottawa |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 285 p. |
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