Cambrian - Ordovician boundary age and duration of the lowest ordovician tremadoc series based on U–Pb zircon dates from Avalonian Wales
By: Landing, E
.
Contributor(s): Bowring, S.A | Davidek, K.L | Rushton, A.W.A | Fortey, R.A | Wimbledon, W.A.P.
Material type: 
ArticleDescription: 485-494pp ; Illustration.Subject(s): Age - Cambrian boundary - Avalonian Wales | Age - Ordovician boundary - Avalonian Wales | Duration - Ordovician tremadoc series - Zircon dates - Avalonian Wales | Volcaniclastic sandstone beds - Brynllin fawr North Wales | Biostratigraphy - Cambrian ordovician boundary - | Volcaniclastic sandstone - Deposition and regional correlation
In:
Geological magazine : Vol. 137 Iss. 1-6 Year. 2000Summary: Abstract
Two thin volcaniclastic sandstone beds in the Bryn-llin-fawr road section in North Wales overlie an apparent sequence boundary within the uppermost Cambrian Acerocare Zone and are overlain by lowest Ordovician (lower Tremadoc) Rhabdinopora faunas. U–Pb geochronology of zircons from these sandstones yields a maximum Cambrian–Ordovician boundary age of 489±0.6 Ma. This age indicates both that the Tremadoc Series (lowest Ordovician) may be shorter in duration than was previously thought and that the duration of the Middle and Late Cambrian (c. 22 Ma) was much less than that of the Early Cambrian (c. 33 Ma). Cambrian trilobite zones locally had an average duration as short as 1 Ma.
| Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Article
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Library and Information Centre Periodical Section | Bound Journal Collection | Not for loan | 002521_105 | ||
Serials/Scientific Journal
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Library and Information Centre Periodical Section | Bound Journal Collection | 550 GEO (Browse shelf) | Available | 002521 |
Abstract
Two thin volcaniclastic sandstone beds in the Bryn-llin-fawr road section in North Wales overlie an apparent sequence boundary within the uppermost Cambrian Acerocare Zone and are overlain by lowest Ordovician (lower Tremadoc) Rhabdinopora faunas. U–Pb geochronology of zircons from these sandstones yields a maximum Cambrian–Ordovician boundary age of 489±0.6 Ma. This age indicates both that the Tremadoc Series (lowest Ordovician) may be shorter in duration than was previously thought and that the duration of the Middle and Late Cambrian (c. 22 Ma) was much less than that of the Early Cambrian (c. 33 Ma). Cambrian trilobite zones locally had an average duration as short as 1 Ma.
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