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
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 A...
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ftboisestateu:oai:scholarworks.boisestate.edu:geo_facpubs-1799 2024-02-04T09:59:22+01:00 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 2023-09-01T07:00:00Z application/pdf https://scholarworks.boisestate.edu/geo_facpubs/794 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1799/viewcontent/Schmitz__Mark__2023__U_Pb_zircon_dates___pub.pdf unknown ScholarWorks https://scholarworks.boisestate.edu/geo_facpubs/794 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1799/viewcontent/Schmitz__Mark__2023__U_Pb_zircon_dates___pub.pdf http://creativecommons.org/licenses/by/4.0/ Geosciences Faculty Publications and Presentations Lower Cambrian Middle Cambrian U-Pb dates Newfoundland Miaolingian Earth Sciences Geophysics and Seismology text 2023 ftboisestateu 2024-01-05T01:12:23Z 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 δ13C 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. Text Breton Island Newfoundland Boise State University: Scholar Works Breton Island ENVELOPE(141.383,141.383,-66.800,-66.800) |
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Open Polar |
collection |
Boise State University: Scholar Works |
op_collection_id |
ftboisestateu |
language |
unknown |
topic |
Lower Cambrian Middle Cambrian U-Pb dates Newfoundland Miaolingian Earth Sciences Geophysics and Seismology |
spellingShingle |
Lower Cambrian Middle Cambrian U-Pb dates Newfoundland Miaolingian Earth Sciences Geophysics and Seismology 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 |
Lower Cambrian Middle Cambrian U-Pb dates Newfoundland Miaolingian Earth Sciences Geophysics and Seismology |
description |
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 δ13C 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 |
Text |
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 |
ScholarWorks |
publishDate |
2023 |
url |
https://scholarworks.boisestate.edu/geo_facpubs/794 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1799/viewcontent/Schmitz__Mark__2023__U_Pb_zircon_dates___pub.pdf |
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 |
Geosciences Faculty Publications and Presentations |
op_relation |
https://scholarworks.boisestate.edu/geo_facpubs/794 https://scholarworks.boisestate.edu/context/geo_facpubs/article/1799/viewcontent/Schmitz__Mark__2023__U_Pb_zircon_dates___pub.pdf |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
_version_ |
1789964150537977856 |