<p> A series of shallow intrusive and extrusive silicic
volcanic rocks near Mamainse Point, Ontario, were sampled and
analyzed for major and trace elements. The rocks are mainly
fine grained, silicified rhyolites grading to dacites
containing phenocrysts of quartz and feldspar.
The analyses performed (XRF, AAS) indicate that many
of these rocks have been altered from the normal igneous
spectrum of rocks to potassic keratophyres. An enrichment
in potash from potash metasomatism has accompanied low
grade, burial metamorphism to produce a secondary mineral
assemblage including chlorite, carbonate, and sericite.
Local intense alteration of some rocks involved the depletion
of mobile alkalis and addition of water and co2 to form
calcite and kaolin.
The overall field and chemical evidence suggest a
single magmatic source for these rocks. </p> / Thesis / Bachelor of Arts (BA)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/18429 |
| Date | 04 1900 |
| Creators | Jackson, Michael R. |
| Contributors | Shaw, Denis, Geology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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