Whole-rock chemical and Sm-Nd isotopie composition of a Late Proterozoic metasedimentary sequence in Ganderia: Kellys Mountain, Bras d'Or terrane, Nova Scotia, Canada

• Published in: Atlantic Geology
• Main Authors: Barr, Sandra M., Pin, Christian, Mcmullin, David W.A., White, Chris E.
• Other Authors: Department of Earth and Environmental Science, Acadia University, Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet Saint-Étienne (UJM)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Nova Scotia Department of Natural Resources
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: geo; archeo; Breton Island; Canada
• Online Access: https://doi.org/10.4138/atlgeol.2013.002; https://hal.archives-ouvertes.fr/hal-01066804

International audience The relationship between law-grade metasedimentary and high-grade paragneissic Precambrian rock units in the Bras d'Or terrane of central Cape Breton Island is a long-standing geological problem. Whole rock geochemical and Nd isotopie data from representative components of these units in the Kellys Mountain area, the Glen Tosh formation and Kellys Mountain Gneiss, show strong similarity. Major and trace element characteristics suggest that protolith sediments for both units were wackes derived from felsic igneous sources and deposited at an active continental margin. Samarium-Nd isotopie data in combination with previously published detrital zircon ages show that the sediments contained an ancient (ca. 2 Ga) end-member of recycled continental crust mixed with a juvenile component of Late Neoproterozoic age. The similarities suggest that the rocks represent the same sedimentary unit at different grades of metamorphism, implying a major crustal break under the area of mixed dioritic and granitic rocks that separates the gneissic and lower grade rocks.