Pattison, David R. M.Hartel, Tijmen H.D.2005-08-052005-08-0519930315831898http://hdl.handle.net/1880/30632Bibliography: p. 188-204.Interlayered tonalitic and mafic gneisses from the Kapuskasing Structural Zone have been metamorphosed to upper-amphibolite/granulite facies. The mafic gneisses are heterogeneous, comprising diopside-garnet-plagioclasesphene- rich (Di-Grt-Pl-Spn) layers, hornblende-plagioclase-rich (Hbl-Pl) layers, and all gradations in between. Plagioclase-quartz-rich (Pl-Qtz) leucosomes occur in a variety of textures in the mafic gneiss, ranging in scale from ?m to dm. Leucosome is generally associated with the hornblende-rich layers and gives the rock a migmatitic appearance. A combination of outcrop textures, microscope textures, modal mineralogy, and mineral analyses suggest that hornblende and plagioclase reacted to form diopside, garnet, sphene and trondhjemitic leucosome. Mass balance analysis, using matrix-algebraic techniques, resulted in the following continuous migmatite-forming reaction consistent with textural, modal and chemical data: Hbl + 0.95 MgFe.1 + Ca-Pl + 0.16 NaSiCa_1A1_1 + 3.42 Qtz => => 1.41 Grt + 1.13 Di+ 0.19 Spn + 1.45 Pl-Qtz (leucosome) Textural, mineralogical and chemical evidence suggest that the plagioclasequartz leucosomes and films (micro-leucosomes) may represent crystallized trondhjemitic melt that formed according to the above dehydration-melting reaction. This is consistent with estimated P-T conditions of 740°C and 9 kbar (=27 km depth) for the KSZ migmatites.xix, 270 leaves : ill. ; 30 cm.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.QE 475 M5 H37 1993aAdditional Copy: QE 475 M5 H37 1993Migmatite - Ontariomaster thesis10.11575/PRISM/15351QE 475 M5 H37 1993a