A Late Neoproterozoic age for a tonalite dyke in the Boisdale Hills, Cape Breton Island, Nova Scotia

Authors

  • Sandra M. Barr Department of Geology, Acadia University, Wolfville, Nova Scotia B0P 1X0, Canada
  • Sandra Kamo Royal Ontario Museum, 100 Queen's Park, Toronto Ontario M5S2C6, Canada
  • Chris E. White Department of Natural Resources, P. O. Box 698, Halifax, Nova Scotia B3J 2T9, Canada

DOI:

https://doi.org/10.4138/2033

Abstract

A tonalite dyke in the Benacadie Brook Formation in the Boisdale Hills of central Cape Breton Island yielded a U-Pb (zircon) age of 564.5 ± 5.1 Ma, interpreted to be the age of intrusion. The age is identical within error to the U-Pb (zircon) age of 564 +3/-2 Ma previously reported for a granodiorite sample from the nearby Shunacadie Pluton. Based on geographic proximity and identical age, as well as petrological similarities, the tonalite dyke is interpreted to be comagmatic with the granodiorite. Although the new date does not provide further constraint on the age of the Benacadie Brook Formation, it affirms the importance of ca. 560 Ma plutonism in the Bras d'Or terrene of Cape Breton Island. RÉSUMÉ Un dyke de tonalite intrusive dans la formation de Benacadie Brook, dans les collines du centre de l’ile du Cap-Breton, a révèlé une datation au U-Pb (au zircon) de 564.5 ± 5.1 m.a. Cette datation est la même que celle obtenue au U-Pb (au zircon) de 564 +3/-2 m.a. signalee précéiemment pour un echantillon de granodiorite de la formation plutonique adjacente de Shunacadie. Compte tenu de la proximité g&jgraphique, du même âge et d'autres similitudes pétrologiques, ce dyke de tonalite est repute appartenir a la mfime province petrographique que la granodiorite. Bien que cette nouvelle datation ne donne pas d'autres précisions sur l’âge de la formation de Benacadie Brook, elle n'en établit pas moins I'importance de l'activité plutonique survenue dans le terrene du Bras d'Or sur l’ile du Cap-Breton il y a environ 560 m.a. Traduit par la rédaction

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Published

1999-10-01

How to Cite

Barr, S. M., Kamo, S., & White, C. E. (1999). A Late Neoproterozoic age for a tonalite dyke in the Boisdale Hills, Cape Breton Island, Nova Scotia. Atlantic Geoscience, 35(3). https://doi.org/10.4138/2033

Issue

Vol. 35 No. 3 (1999)

Section

Articles

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