The northern Appalachian orogen preserves evidence of a complex history of amalgamation of terranes with both Laurentian and Gondwanan affinities. The Ganderian Bras d’Or terrane of central Cape Breton Island is not well represented elsewhere in the orogen and its relationship to other Ganderian terranes is enigmatic, particularly with respect to its pre-Neoproterozoic history. The Boisdale Hills and Kellys Mountain areas contain the oldest metamorphic rocks in the Bras d’Or terrane. Quartzite units in the Boisdale Hills have detrital zircon populations with ages ranging from 3.2 to ca. 1 Ga. Paragneiss units from the Kellys Mountain area contain Meso- to Neoproterozoic detrital zircons, in which the youngest grains indicate that the maximum depositional age is <600 Ma. The detrital zircon populations of rocks from both areas are consistent with Gondwanan provenance for the protoliths, most likely the Amazonian craton. New U–Pb dates for subduction-related dioritic to granodioritic plutons in the Boisdale Hills yielded ages of 560 to ca. 540 Ma. Sedimentary, bimodal volcanic and plutonic rocks from the Bourinot belt in the Boisdale Hills and related plutons in the Kellys Mountain area have ages of ca. 510–490 Ma and are interpreted to have formed during extension related to separation of Ganderia from Gondwana. The southeastern Bras d’Or terrane preserves rocks formed in Pan-African subduction zones on a former passive margin of Gondwana as well as rocks formed during the initial stages of rifting of Ganderia from Gondwana and the subsequent opening of the Rheic Ocean.
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Research Article|
February 07, 2019
New U–Pb age constraints on the geological history of the Ganderian Bras d’Or terrane, Cape Breton Island, Nova Scotia
D. van Rooyen;
a
Department of Mathematics, Physics, and Geology, Cape Breton University, Sydney, NS B1P 6L2, Canada.Corresponding author: Deanne van Rooyen (email: [email protected]).
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S.M. Barr;
S.M. Barr
b
Department of Earth and Environmental Science, Acadia University, Wolfville, NS B4P 2R6, Canada.
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C.E. White;
C.E. White
c
Nova Scotia Department of Energy and Mines, Halifax, NS B3J 2T9, Canada.
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M.A. Hamilton
M.A. Hamilton
d
Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada.
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a
Department of Mathematics, Physics, and Geology, Cape Breton University, Sydney, NS B1P 6L2, Canada.
S.M. Barr
b
Department of Earth and Environmental Science, Acadia University, Wolfville, NS B4P 2R6, Canada.
C.E. White
c
Nova Scotia Department of Energy and Mines, Halifax, NS B3J 2T9, Canada.
M.A. Hamilton
d
Department of Earth Sciences, University of Toronto, Toronto, ON M5S 3B1, Canada.Corresponding author: Deanne van Rooyen (email: [email protected]).
Publisher: Canadian Science Publishing
Received:
21 Sep 2018
Accepted:
02 Feb 2019
First Online:
28 Aug 2019
Online ISSN: 1480-3313
Print ISSN: 0008-4077
Published by NRC Research Press
Canadian Journal of Earth Sciences (2019) 56 (8): 829–847.
Article history
Received:
21 Sep 2018
Accepted:
02 Feb 2019
First Online:
28 Aug 2019
Citation
D. van Rooyen, S.M. Barr, C.E. White, M.A. Hamilton; New U–Pb age constraints on the geological history of the Ganderian Bras d’Or terrane, Cape Breton Island, Nova Scotia. Canadian Journal of Earth Sciences 2019;; 56 (8): 829–847. doi: https://doi.org/10.1139/cjes-2018-0248
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Index Terms/Descriptors
- absolute age
- Appalachians
- Cambrian
- Canada
- Cape Breton Island
- diorites
- Eastern Canada
- Ediacaran
- Gander Zone
- gneisses
- granites
- igneous rocks
- intrusions
- Maritime Provinces
- metamorphic rocks
- metasedimentary rocks
- Neoproterozoic
- nesosilicates
- North America
- Northern Appalachians
- Nova Scotia
- orthosilicates
- Paleozoic
- paragneiss
- plutonic rocks
- plutons
- Precambrian
- Proterozoic
- silicates
- U/Pb
- upper Precambrian
- zircon
- zircon group
- Bras d'Or Terrane
- Boisdale Hills
- Bourinot Group
- Frenchvale Road Metamorphic Suite
- Kellys Mountain
- Eskasoni Formation
- Boisdale Hills Pluton
Latitude & Longitude
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