Skip to Main Content
Book Chapter

The Notre Dame arc and the Taconic orogeny in Newfoundland

By
C.R. van Staal
C.R. van Staal
Geological Survey of Canada, NRCan, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada, and Department of Earth Sciences, University of Ottawa, and Ottawa-Carleton Geoscience Centre, 140 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
Search for other works by this author on:
J.B. Whalen
J.B. Whalen
Geological Survey of Canada, NRCan, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada
Search for other works by this author on:
V.J. McNicoll
V.J. McNicoll
Geological Survey of Canada, NRCan, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada
Search for other works by this author on:
S. Pehrsson
S. Pehrsson
Geological Survey of Canada, NRCan, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada
Search for other works by this author on:
C.J. Lissenberg
C.J. Lissenberg
Department of Earth Sciences, University of Ottawa, and Ottawa-Carleton Geoscience Centre, 140 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
Search for other works by this author on:
A. Zagorevski
A. Zagorevski
Geological Survey of Canada, NRCan, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada, and Department of Earth Sciences, University of Ottawa, and Ottawa-Carleton Geoscience Centre, 140 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
Search for other works by this author on:
O. van Breemen
O. van Breemen
Geological Survey of Canada, NRCan, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada
Search for other works by this author on:
G.A. Jenner
G.A. Jenner
Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X5, Canada
Search for other works by this author on:
Published:
January 01, 2007

The Taconic orogeny in Newfoundland consisted of three accretionary events (Taconic 1, 2, and 3). Taconic 1 is represented by ca. 495 Ma, west-directed obduction of the infant-arc Lushs Bight oceanic tract (510–501 Ma) onto the peri-Laurentian Dashwoods microcontinent. Subduction is inferred to have initiated at a spreading center abandoned during an inboard ridge jump responsible for separation of Dash-woods from Laurentia and opening of the Humber seaway. Clogging of the subduction zone by Dashwoods forced subduction to step back into the Humber seaway. Inception of the new subduction zone led to formation of the ca. 490 Ma Baie Verte oceanic tract.

Closure of the Humber seaway formed the Notre Dame arc (489–477 Ma) built on Dashwoods and the coeval Snooks Arm arc built on the Baie Verte oceanic tract. Sea-way closure led to collision (Taconic 2) between the arcs and Laurentia, which caused significant shortening of the Notre Dame arc. After a magmatic gap of 7–10 m.y., the Notre Dame arc records a voluminous flare-up of predominantly tonalite magmatism (464–459 Ma) during the waning stages of Taconic 2. Magmatism overlaps with deformation and includes both arc and non-arc-like tonalite. This flare-up was related to break-off of the oceanic lithosphere of the downgoing slab. The rapidly upwelling asthenosphere that replaced the broken-off slab induced melting in the subarc mantle and arc infrastructure.

Taconic 3 is represented by 455–450 Ma accretion of a peri-Laurentian arc that had formed after the ca. 480 Ma initiation of west-directed subduction in the Iapetus Ocean outboard of the Dashwoods microcontinent.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Memoirs

4-D Framework of Continental Crust

Robert D. Hatcher, Jr.
Robert D. Hatcher, Jr.
Search for other works by this author on:
Marvin P. Carlson
Marvin P. Carlson
Search for other works by this author on:
John H. McBride
John H. McBride
Search for other works by this author on:
José R. Martínez Catalán
José R. Martínez Catalán
Search for other works by this author on:
Geological Society of America
Volume
200
ISBN print:
9780813712000
Publication date:
January 01, 2007

References

Related

Citing Books via

A comprehensive resource of eBooks for researchers in the Earth Sciences

Related Articles
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal