The Thetford-Black Lake area, Megantic County, Quebec, has been one of the most important producers of chrysotile asbestos for over 60 years. The asbestos has been obtained either from a large mass of partly serpentinized peridotite, thought to be laccolithic in shape, or from a narrow body of serpentinized peridotite that parallels the structural trend of the area, known as the Pennington Dyke. The mines and open pit workings of the larger mass have always encountered light-coloured holocrystalline dykes which vary in composition from a diorite to a quartzitic vein, but which are always referred to by the miners and mine operators as "granite". Small deposits of chromite are found in the same mass, associated with an olivine-rich phase of the peridotite. Here again, "granite" dykes are encountered, although not as extensively as in the asbestos workings. The object of this thesis is, by the study of published reports on these acidic intrusives and with the help of some original studies, to report on their petrographic character and their distribution, and draw conclusions as to their age, origin, and economic importance.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.108605 |
| Date | January 1952 |
| Creators | Gorman, W.A. |
| Contributors | Stevenson, J.S. (Supervisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science. (Department of Geological Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: NNNNNNNNN, Theses scanned by McGill Library. |
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