The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada
Abstract Sections exposing the Cambrian–Ordovician Boundary interval at Broom Point in western Newfoundland have been proposed earlier for a global systemic boundary stratotype. These lie within the Cow Head Group, a late Middle Cambrian to early Middle Ordovician allochthonous unit of limestone, sh...
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Cambridge University Press (CUP)
1988
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Online Access: | http://dx.doi.org/10.1017/s0016756800013042 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800013042 |
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crcambridgeupr:10.1017/s0016756800013042 2024-06-23T07:54:45+00:00 The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada Barnes, C. R. 1988 http://dx.doi.org/10.1017/s0016756800013042 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800013042 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Geological Magazine volume 125, issue 4, page 381-414 ISSN 0016-7568 1469-5081 journal-article 1988 crcambridgeupr https://doi.org/10.1017/s0016756800013042 2024-06-05T04:02:40Z Abstract Sections exposing the Cambrian–Ordovician Boundary interval at Broom Point in western Newfoundland have been proposed earlier for a global systemic boundary stratotype. These lie within the Cow Head Group, a late Middle Cambrian to early Middle Ordovician allochthonous unit of limestone, shale, and conglomerate deposited at the toe of the ancient continental slope and on the adjacent continental rise. Several recent studies have further investigated the stratigraphy, sedimentology, and palaeontology of the Cow Head Group and others are under way on magnetostratigraphy and chemostratigraphy. These aspects are reviewed for six key boundary sections representing proximal to distal facies: Cow Head Ledge, Broom Point South, Broom Point North, St Pauls Inlet Quarry, Martin Point, and Green Point. In particular, new data are presented from 260 conodont samples that yielded 15500 conodonts. This intense sampling has allowed the discrimination of minor hiatuses in the proximal to intermediate facies where conglomerates have eroded and cannibalized underlying strata. New conodont data from Broom Point North have lowered the base of the C. lindstromi Zone into unit 74 conglomerates, thereby making this section unsuitable as a boundary stratotype. New collections from Green Point have yielded abundant conodonts and over 9400 conodonts have been recovered from 77 samples. The conodont, graptolite, and trilobite biostratigraphy through the boundary interval is documented allowing accurate correlation between sections and more precisely revealing small hiatuses in the proximal and intermediate facies. The sequence of conodont zones is: Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedius, C. lindstromi and C. angulatus. These can be correlated with trilobite zones established from both in situ and clast faunas from the proximal to intermediate facies and with graptolite assemblages (of Cooper 1979) especially in the intermediate to distal facies. Three new species of Cordylodus are described ( ... Article in Journal/Newspaper Newfoundland Cambridge University Press Canada The Toe ENVELOPE(-59.167,-59.167,-62.333,-62.333) Cow Head ENVELOPE(-57.832,-57.832,49.917,49.917) Green Point ENVELOPE(73.350,73.350,-53.083,-53.083) St. Pauls ENVELOPE(-57.815,-57.815,49.867,49.867) Broom Point ENVELOPE(-57.865,-57.865,49.833,49.833) Martin Point ENVELOPE(-44.683,-44.683,-60.767,-60.767) St. Pauls Inlet ENVELOPE(-57.748,-57.748,49.833,49.833) Geological Magazine 125 4 381 414 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract Sections exposing the Cambrian–Ordovician Boundary interval at Broom Point in western Newfoundland have been proposed earlier for a global systemic boundary stratotype. These lie within the Cow Head Group, a late Middle Cambrian to early Middle Ordovician allochthonous unit of limestone, shale, and conglomerate deposited at the toe of the ancient continental slope and on the adjacent continental rise. Several recent studies have further investigated the stratigraphy, sedimentology, and palaeontology of the Cow Head Group and others are under way on magnetostratigraphy and chemostratigraphy. These aspects are reviewed for six key boundary sections representing proximal to distal facies: Cow Head Ledge, Broom Point South, Broom Point North, St Pauls Inlet Quarry, Martin Point, and Green Point. In particular, new data are presented from 260 conodont samples that yielded 15500 conodonts. This intense sampling has allowed the discrimination of minor hiatuses in the proximal to intermediate facies where conglomerates have eroded and cannibalized underlying strata. New conodont data from Broom Point North have lowered the base of the C. lindstromi Zone into unit 74 conglomerates, thereby making this section unsuitable as a boundary stratotype. New collections from Green Point have yielded abundant conodonts and over 9400 conodonts have been recovered from 77 samples. The conodont, graptolite, and trilobite biostratigraphy through the boundary interval is documented allowing accurate correlation between sections and more precisely revealing small hiatuses in the proximal and intermediate facies. The sequence of conodont zones is: Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedius, C. lindstromi and C. angulatus. These can be correlated with trilobite zones established from both in situ and clast faunas from the proximal to intermediate facies and with graptolite assemblages (of Cooper 1979) especially in the intermediate to distal facies. Three new species of Cordylodus are described ( ... |
format |
Article in Journal/Newspaper |
author |
Barnes, C. R. |
spellingShingle |
Barnes, C. R. The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada |
author_facet |
Barnes, C. R. |
author_sort |
Barnes, C. R. |
title |
The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada |
title_short |
The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada |
title_full |
The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada |
title_fullStr |
The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada |
title_full_unstemmed |
The proposed Cambrian–Ordovician global Boundary stratotype and point (GSSP) in Western Newfoundland, Canada |
title_sort |
proposed cambrian–ordovician global boundary stratotype and point (gssp) in western newfoundland, canada |
publisher |
Cambridge University Press (CUP) |
publishDate |
1988 |
url |
http://dx.doi.org/10.1017/s0016756800013042 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016756800013042 |
long_lat |
ENVELOPE(-59.167,-59.167,-62.333,-62.333) ENVELOPE(-57.832,-57.832,49.917,49.917) ENVELOPE(73.350,73.350,-53.083,-53.083) ENVELOPE(-57.815,-57.815,49.867,49.867) ENVELOPE(-57.865,-57.865,49.833,49.833) ENVELOPE(-44.683,-44.683,-60.767,-60.767) ENVELOPE(-57.748,-57.748,49.833,49.833) |
geographic |
Canada The Toe Cow Head Green Point St. Pauls Broom Point Martin Point St. Pauls Inlet |
geographic_facet |
Canada The Toe Cow Head Green Point St. Pauls Broom Point Martin Point St. Pauls Inlet |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Geological Magazine volume 125, issue 4, page 381-414 ISSN 0016-7568 1469-5081 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0016756800013042 |
container_title |
Geological Magazine |
container_volume |
125 |
container_issue |
4 |
container_start_page |
381 |
op_container_end_page |
414 |
_version_ |
1802647019330732032 |