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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The petrology, mineralogy and geochemistry of the Cinder Lake alkaline intrusive complex, eastern Manitoba

Kressall, Ryan 05 January 2012 (has links)
A suite of silica-undersaturated syenites outcrops along the margins of a monzogranite pluton emplaced in the Knee Lake greenstone belt at Cinder Lake, Manitoba. Alkali-feldspar syenitic pegmatite probably represents a cumulate unit derived from magma that subsequently evolved to fine-grained feldspathoid syenites. This evolution involved an increase in the degree of undersaturation from cancrinite-nepheline syenite to vishnevite syenite. Abundant calcite veinlets, showing a carbonatitic isotopic and trace-element signature, crosscut the pegmatite and are interpreted to have evolved from the syenites. The monzogranite and syenites gave similar radiometric ages (~2.72 Ga), but evidence of fenitization in the former suggests that the syenites are somewhat younger. The emplacement of these rocks was coeval with the collision of the North Caribou and North Superior superterranes during amalgamation of the Superior Province. The observed transition from granitic to alkaline magmatism is interpreted to mark the transition from a collisional to post-collisional tectonic regime.
2

The petrology, mineralogy and geochemistry of the Cinder Lake alkaline intrusive complex, eastern Manitoba

Kressall, Ryan 05 January 2012 (has links)
A suite of silica-undersaturated syenites outcrops along the margins of a monzogranite pluton emplaced in the Knee Lake greenstone belt at Cinder Lake, Manitoba. Alkali-feldspar syenitic pegmatite probably represents a cumulate unit derived from magma that subsequently evolved to fine-grained feldspathoid syenites. This evolution involved an increase in the degree of undersaturation from cancrinite-nepheline syenite to vishnevite syenite. Abundant calcite veinlets, showing a carbonatitic isotopic and trace-element signature, crosscut the pegmatite and are interpreted to have evolved from the syenites. The monzogranite and syenites gave similar radiometric ages (~2.72 Ga), but evidence of fenitization in the former suggests that the syenites are somewhat younger. The emplacement of these rocks was coeval with the collision of the North Caribou and North Superior superterranes during amalgamation of the Superior Province. The observed transition from granitic to alkaline magmatism is interpreted to mark the transition from a collisional to post-collisional tectonic regime.

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