The age of the Roberts Arm Group, north-central Newfoundland
Felsites from the Roberts Arm Group have yielded a Rb–Sr isochron age of 447 ± 7 Ma, with an initial 87 Sr/ 86 Sr of 0.7063, and a genetically related granite pluton has yielded an isochron age of 464 ± 13 Ma, with an initial ratio of 0.7064. The Mansfield Cove oceanic plagiogranite complex, which i...
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crcansciencepubl:10.1139/e79-055 2023-12-17T10:43:37+01:00 The age of the Roberts Arm Group, north-central Newfoundland Bostock, H. H. Currie, K. L. Wanless, R. K. 1979 http://dx.doi.org/10.1139/e79-055 http://www.nrcresearchpress.com/doi/pdf/10.1139/e79-055 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 16, issue 3, page 599-606 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 1979 crcansciencepubl https://doi.org/10.1139/e79-055 2023-11-19T13:38:47Z Felsites from the Roberts Arm Group have yielded a Rb–Sr isochron age of 447 ± 7 Ma, with an initial 87 Sr/ 86 Sr of 0.7063, and a genetically related granite pluton has yielded an isochron age of 464 ± 13 Ma, with an initial ratio of 0.7064. The Mansfield Cove oceanic plagiogranite complex, which is in fault contact with the Roberts Arm Group, has yielded a minimum zircon 207 Pb/ 206 Pb age of 594 ± 10 Ma. This plagiogranite, and basaltic rocks of the Hall Hill complex which partly surround it, thus provide a basement of suitable age upon which the Roberts Arm Group may have been deposited. The age of this basement corresponds to that of the opening of the lapetus Ocean.The stratigraphic age of the Roberts Arm Group, indicated by these ages, is Middle or possibly Late Ordovician. The volcanics were deposited either before or slightly after the Caradocian black shales of the Notre Dame Bay region. In the former case, Ordovician volcanism around western Notre Dame Bay ceased at about the time of obduction of the allochthons of western Newfoundland. In the latter, volcanism of the Roberts Arm Group marks a north to westward shift of volcanism within the central mobile belt of Newfoundland that occurred in late Middle or early Late Ordovician time. If the Buchans Group is of Silurian age and correlative with the Roberts Arm Group then this lithostratigraphic unit is probably diachronous, younging to the south. Article in Journal/Newspaper Newfoundland Canadian Science Publishing (via Crossref) Notre Dame Bay ENVELOPE(-54.998,-54.998,49.750,49.750) Mansfield ENVELOPE(-45.733,-45.733,-60.650,-60.650) Canadian Journal of Earth Sciences 16 3 599 606 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Bostock, H. H. Currie, K. L. Wanless, R. K. The age of the Roberts Arm Group, north-central Newfoundland |
topic_facet |
General Earth and Planetary Sciences |
description |
Felsites from the Roberts Arm Group have yielded a Rb–Sr isochron age of 447 ± 7 Ma, with an initial 87 Sr/ 86 Sr of 0.7063, and a genetically related granite pluton has yielded an isochron age of 464 ± 13 Ma, with an initial ratio of 0.7064. The Mansfield Cove oceanic plagiogranite complex, which is in fault contact with the Roberts Arm Group, has yielded a minimum zircon 207 Pb/ 206 Pb age of 594 ± 10 Ma. This plagiogranite, and basaltic rocks of the Hall Hill complex which partly surround it, thus provide a basement of suitable age upon which the Roberts Arm Group may have been deposited. The age of this basement corresponds to that of the opening of the lapetus Ocean.The stratigraphic age of the Roberts Arm Group, indicated by these ages, is Middle or possibly Late Ordovician. The volcanics were deposited either before or slightly after the Caradocian black shales of the Notre Dame Bay region. In the former case, Ordovician volcanism around western Notre Dame Bay ceased at about the time of obduction of the allochthons of western Newfoundland. In the latter, volcanism of the Roberts Arm Group marks a north to westward shift of volcanism within the central mobile belt of Newfoundland that occurred in late Middle or early Late Ordovician time. If the Buchans Group is of Silurian age and correlative with the Roberts Arm Group then this lithostratigraphic unit is probably diachronous, younging to the south. |
format |
Article in Journal/Newspaper |
author |
Bostock, H. H. Currie, K. L. Wanless, R. K. |
author_facet |
Bostock, H. H. Currie, K. L. Wanless, R. K. |
author_sort |
Bostock, H. H. |
title |
The age of the Roberts Arm Group, north-central Newfoundland |
title_short |
The age of the Roberts Arm Group, north-central Newfoundland |
title_full |
The age of the Roberts Arm Group, north-central Newfoundland |
title_fullStr |
The age of the Roberts Arm Group, north-central Newfoundland |
title_full_unstemmed |
The age of the Roberts Arm Group, north-central Newfoundland |
title_sort |
age of the roberts arm group, north-central newfoundland |
publisher |
Canadian Science Publishing |
publishDate |
1979 |
url |
http://dx.doi.org/10.1139/e79-055 http://www.nrcresearchpress.com/doi/pdf/10.1139/e79-055 |
long_lat |
ENVELOPE(-54.998,-54.998,49.750,49.750) ENVELOPE(-45.733,-45.733,-60.650,-60.650) |
geographic |
Notre Dame Bay Mansfield |
geographic_facet |
Notre Dame Bay Mansfield |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Canadian Journal of Earth Sciences volume 16, issue 3, page 599-606 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e79-055 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
16 |
container_issue |
3 |
container_start_page |
599 |
op_container_end_page |
606 |
_version_ |
1785558782781161472 |