U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit
Abstract High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma ( Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma ( Morocconus-Condyl...
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2023
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Online Access: | http://dx.doi.org/10.1017/s0016756823000729 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756823000729 |
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crcambridgeupr:10.1017/s0016756823000729 2024-03-03T08:43:21+00:00 U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit Landing, Ed Schmitz, Mark D. Westrop, Stephen R. Geyer, Gerd 2023 http://dx.doi.org/10.1017/s0016756823000729 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756823000729 en eng Cambridge University Press (CUP) http://creativecommons.org/licenses/by/4.0/ Geological Magazine volume 160, issue 9, page 1790-1816 ISSN 0016-7568 1469-5081 Geology journal-article 2023 crcambridgeupr https://doi.org/10.1017/s0016756823000729 2024-02-08T08:26:01Z Abstract High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma ( Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma ( Morocconus-Condylopyge eli Assemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma ( Kiskinella cristata Zone) and 506.25 ± 0.07 Ma ( Eccaparadoxides bennetti Zone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 and 506.3 ± 0.2 Ma is consistent with maximum depositional age constraints from southwest Laurentia, which indicate an age for the base of the Miaolingian Series, as locally interpreted, of ≤ 506.6 ± 0.3 Ma. The Miaolingian Series’ base is interpreted as correlative within ≤ 0.3 ± 0.3 Ma between Cambrian palaeocontinents, although its exact synchrony is questionable due to taxonomic problems with a possible Oryctocephalus indicus -plexus, invariable dysoxic lithofacies control of O. indicus and diachronous occurrence of O. indicus in temporally distinct δ 13 C chemozones in South China and SW Laurentia. The lowest occurrence of O. indicus assemblages is linked to onlap (epeirogenic or eustatic) of dysoxic facies. A united Avalonia is shown by late Early Cambrian volcanics in SW New Brunswick; Cape Breton Island; SE Newfoundland; and the Wrekin area, England. The new U-Pb ages revise Avalonian geological evolution as they show rapid epeirogenic changes through depositional sequences 4a–6. Article in Journal/Newspaper Breton Island Newfoundland Cambridge University Press Breton Island ENVELOPE(141.383,141.383,-66.800,-66.800) Geological Magazine 160 9 1790 1816 |
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Geology |
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Geology Landing, Ed Schmitz, Mark D. Westrop, Stephen R. Geyer, Gerd U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit |
topic_facet |
Geology |
description |
Abstract High-precision U-Pb zircon ages on SE Newfoundland tuffs now bracket the Avalonian Lower–Middle Cambrian boundary. Upper Lower Cambrian Brigus Formation tuffs yield depositional ages of 507.91 ± 0.07 Ma ( Callavia broeggeri Zone) and 507.67 ± 0.08 Ma and 507.21 ± 0.13 Ma ( Morocconus-Condylopyge eli Assemblage interval). Lower Middle Cambrian Chamberlain’s Brook Formation tuffs have depositional ages of 506.34 ± 0.21 Ma ( Kiskinella cristata Zone) and 506.25 ± 0.07 Ma ( Eccaparadoxides bennetti Zone). The composite unconformity separating the Brigus and Chamberlain’s Brook formations is constrained between these ages. An Avalonian Lower–Middle Cambrian boundary between 507.2 ± 0.1 and 506.3 ± 0.2 Ma is consistent with maximum depositional age constraints from southwest Laurentia, which indicate an age for the base of the Miaolingian Series, as locally interpreted, of ≤ 506.6 ± 0.3 Ma. The Miaolingian Series’ base is interpreted as correlative within ≤ 0.3 ± 0.3 Ma between Cambrian palaeocontinents, although its exact synchrony is questionable due to taxonomic problems with a possible Oryctocephalus indicus -plexus, invariable dysoxic lithofacies control of O. indicus and diachronous occurrence of O. indicus in temporally distinct δ 13 C chemozones in South China and SW Laurentia. The lowest occurrence of O. indicus assemblages is linked to onlap (epeirogenic or eustatic) of dysoxic facies. A united Avalonia is shown by late Early Cambrian volcanics in SW New Brunswick; Cape Breton Island; SE Newfoundland; and the Wrekin area, England. The new U-Pb ages revise Avalonian geological evolution as they show rapid epeirogenic changes through depositional sequences 4a–6. |
format |
Article in Journal/Newspaper |
author |
Landing, Ed Schmitz, Mark D. Westrop, Stephen R. Geyer, Gerd |
author_facet |
Landing, Ed Schmitz, Mark D. Westrop, Stephen R. Geyer, Gerd |
author_sort |
Landing, Ed |
title |
U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit |
title_short |
U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit |
title_full |
U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit |
title_fullStr |
U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit |
title_full_unstemmed |
U-Pb zircon dates from North American and British Avalonia bracket the Lower–Middle Cambrian boundary interval, with evaluation of the Miaolingian Series as a global unit |
title_sort |
u-pb zircon dates from north american and british avalonia bracket the lower–middle cambrian boundary interval, with evaluation of the miaolingian series as a global unit |
publisher |
Cambridge University Press (CUP) |
publishDate |
2023 |
url |
http://dx.doi.org/10.1017/s0016756823000729 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756823000729 |
long_lat |
ENVELOPE(141.383,141.383,-66.800,-66.800) |
geographic |
Breton Island |
geographic_facet |
Breton Island |
genre |
Breton Island Newfoundland |
genre_facet |
Breton Island Newfoundland |
op_source |
Geological Magazine volume 160, issue 9, page 1790-1816 ISSN 0016-7568 1469-5081 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1017/s0016756823000729 |
container_title |
Geological Magazine |
container_volume |
160 |
container_issue |
9 |
container_start_page |
1790 |
op_container_end_page |
1816 |
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1792498775689789440 |