PETROGRAPHY OF METAMORPHOSED PRECAMBRIAN METASEDIMENTARY ROCKS AND INTRUDING MAFIC DYKES, FRONTENAC ARC, SOUTHEASTERN ONTARIO, CANADA

The Queen’s University Biology Station (QUBS) located north of Kingston, Ontario is located on the Frontenac terrane, a Meso- to Neoproterozoic suite of metasedimentary platformal rocks, intruding mafic dikes and granitoid plutons deformed during the Grenvillian orogenic cycle. The dykes are believed to be part of the Kingston (c. 1.1 GA) and Rideau swarms (c. 800 MA). Near QUBS, these rocks are overlain by undeformed Paleozoic clastic and carbonate strata. Precambrian sequences were metamorphosed to amphibolite grade during the Grenville orogeny, but the combination of excellent exposure and good preservation permits examination of the petrography and alteration history of the metasedimentary rocks that were intruded by the dikes. Contact metamorphic aureoles are particularly well preserved around dikes that cut through carbonate sequences. In this presentation, we present preliminary results from a undergraduate petrographic survey of samples collected across metamorphic aureoles adjacent to dikes in the vicinity of QUBS. Visible aureole intervals measure from cm to dm across and consist of wollastonite and other medium-high grade metamorphic minerals. The protoliths are marbles and dolomitic marble.