Stratigraphy, structure and metamorphic petrology of the Archean greenstone belt at Bird River, Manitoba
Trueman, David Lawrence.
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The development of the earth's crust in the Bird River area of southeastern Manitoba involved volcanism, erosion, sedimentation, folding, and metamorphism which terminated during the Kenoran event of the Canadian Shield. The rocks, so formed and known as the Bird River greenstone belt, are present in the study area as a wedge of greenschist and amphibotite facies metamorphites situated between gneissic rocks to the north known as the Manigotagan gneiss belt, and intrusive and gneissic rocks to the south termed the Winnipeg River batholithic belt. Mapping on outcrop scale, petrographic, structural, and chemical analysis of the rocks of the Bird River area conducted over a period of six years have allowed a six-fold subdivision of rocks of the greenstone belt... The metavolcanic and related metasedimentary rocks of these formations have been intruded by synvolcanic counterparts, and all of the rocks of the stratigraphic section were subsequently intruded during metamorphism by diapiric batholiths. Late intrusive rocks, post-dating major metamorphism, include batholiths of quartz monzonite and stocks and dykes of pegmatite kindred... The youngest metamorphic event recognized in the area was essentially retrogressive and accompanied by the development of easterly trending faults which served to telescope the stratigraphic succession of the belt, and served as loci for subsequent granite and pegmatite intrusion.