Date of Award

2015

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Earth and Environmental Sciences

First Advisor

Gagnon, Joel

Second Advisor

Polat, Ali

Keywords

Geochemistry, Geodynamics, Lynn Lake, Metallogeny, Rifted continental margin, Trans-Hudson Orogen

Rights

CC BY-NC-ND 4.0

Abstract

The MacLellan Au-Ag deposit, located in the Paleoproterozoic Lynn Lake greenstone belt of the Trans-Hudson Orogen, Manitoba, is hosted by a package of plagioclase-amphibole, chlorite-amphibole, and quartz-plagioclase-biotite schists that are considered to be representative of the geodynamic evolution of the northern section of the Lynn Lake greenstone belt. A combination of field and petrographic observations and high-precision trace element chemistry have identified the protoliths to the host rock sequence as transitional aluminous basalt with subordinate picrite and biotite-altered aluminous basalt, respectively. The Th-Nb-La-REE systematics of these rocks are consistent with a rifted continental margin environment. Volcanic rocks with similar Th-Nb-La-REE systematics to those from the MacLellan host rock sequence have been identified throughout the Lynn Lake region. Therefore, it is proposed that the Lynn Lake greenstone belt represents a rifted continental margin and based on this revised geodynamic model, the mineral potential of the belt should be reassessed.

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