Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation
Abstract The δ 13 C profile from an interval of the Martin Point section in western Newfoundland (Canada) spans the upper Furongian (uppermost Cambrian). The interval (~90 m) is a part of the Green Point Formation of the Cow Head Group and consists of the Martin Point (lower) and the Broom Point (up...
Published in: | Geological Magazine |
---|---|
Main Author: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Cambridge University Press (CUP)
2018
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1017/s001675681800002x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S001675681800002X |
id |
crcambridgeupr:10.1017/s001675681800002x |
---|---|
record_format |
openpolar |
spelling |
crcambridgeupr:10.1017/s001675681800002x 2024-06-23T07:54:48+00:00 Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation AZMY, KAREM 2018 http://dx.doi.org/10.1017/s001675681800002x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S001675681800002X en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Geological Magazine volume 156, issue 5, page 759-771 ISSN 0016-7568 1469-5081 journal-article 2018 crcambridgeupr https://doi.org/10.1017/s001675681800002x 2024-06-12T04:04:00Z Abstract The δ 13 C profile from an interval of the Martin Point section in western Newfoundland (Canada) spans the upper Furongian (uppermost Cambrian). The interval (~90 m) is a part of the Green Point Formation of the Cow Head Group and consists of the Martin Point (lower) and the Broom Point (upper) members. It is formed of slope marine carbonates alternating with shales (rhythmites) and conglomeratic interbeds. The preservation of the investigated micritic carbonates was meticulously evaluated by multiple petrographic and geochemical screening tools. The δ 13 C and δ 18 O values (−0.5 ± 0.8 ‰VPDB and −7.1 ± 0.3 ‰VPDB, respectively) exhibit insignificant correlation ( R 2 = 0.002) and similarly the correlation of δ 13 C values with their Sr and Mn counterparts, which supports the preservation of at least near-primary δ 13 C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ 13 C profile exhibits two main negative excursions, a lower broad excursion (~3 ‰) that reaches its maximum at ~70 m below the Martin Point / Broom Point members boundary and an upper narrow excursion (~2.5 ‰) immediately below the same boundary. The lower excursion can be correlated with the global latest Furongian HERB event (TOCE), which is also recognized in the C-isotope profile of the GSSP boundary section at Green Point whereas the upper excursion matches with that of the Cambrian‒Ordovician boundary in the same section. The peak of the HERB δ 13 C excursion is correlated with positive shifts on the Th/U and Ni profiles (redox and productivity proxies). Article in Journal/Newspaper Newfoundland Cambridge University Press Canada Cow Head ENVELOPE(-57.832,-57.832,49.917,49.917) Green Point ENVELOPE(73.350,73.350,-53.083,-53.083) Broom Point ENVELOPE(-57.865,-57.865,49.833,49.833) Martin Point ENVELOPE(-44.683,-44.683,-60.767,-60.767) Geological Magazine 156 5 759 771 |
institution |
Open Polar |
collection |
Cambridge University Press |
op_collection_id |
crcambridgeupr |
language |
English |
description |
Abstract The δ 13 C profile from an interval of the Martin Point section in western Newfoundland (Canada) spans the upper Furongian (uppermost Cambrian). The interval (~90 m) is a part of the Green Point Formation of the Cow Head Group and consists of the Martin Point (lower) and the Broom Point (upper) members. It is formed of slope marine carbonates alternating with shales (rhythmites) and conglomeratic interbeds. The preservation of the investigated micritic carbonates was meticulously evaluated by multiple petrographic and geochemical screening tools. The δ 13 C and δ 18 O values (−0.5 ± 0.8 ‰VPDB and −7.1 ± 0.3 ‰VPDB, respectively) exhibit insignificant correlation ( R 2 = 0.002) and similarly the correlation of δ 13 C values with their Sr and Mn counterparts, which supports the preservation of at least near-primary δ 13 C signatures that can be utilized to construct a reliable high-resolution carbon-isotope profile for global correlations. The δ 13 C profile exhibits two main negative excursions, a lower broad excursion (~3 ‰) that reaches its maximum at ~70 m below the Martin Point / Broom Point members boundary and an upper narrow excursion (~2.5 ‰) immediately below the same boundary. The lower excursion can be correlated with the global latest Furongian HERB event (TOCE), which is also recognized in the C-isotope profile of the GSSP boundary section at Green Point whereas the upper excursion matches with that of the Cambrian‒Ordovician boundary in the same section. The peak of the HERB δ 13 C excursion is correlated with positive shifts on the Th/U and Ni profiles (redox and productivity proxies). |
format |
Article in Journal/Newspaper |
author |
AZMY, KAREM |
spellingShingle |
AZMY, KAREM Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation |
author_facet |
AZMY, KAREM |
author_sort |
AZMY, KAREM |
title |
Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation |
title_short |
Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation |
title_full |
Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation |
title_fullStr |
Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation |
title_full_unstemmed |
Carbon-isotope stratigraphy of the uppermost Cambrian in eastern Laurentia: implications for global correlation |
title_sort |
carbon-isotope stratigraphy of the uppermost cambrian in eastern laurentia: implications for global correlation |
publisher |
Cambridge University Press (CUP) |
publishDate |
2018 |
url |
http://dx.doi.org/10.1017/s001675681800002x https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S001675681800002X |
long_lat |
ENVELOPE(-57.832,-57.832,49.917,49.917) ENVELOPE(73.350,73.350,-53.083,-53.083) ENVELOPE(-57.865,-57.865,49.833,49.833) ENVELOPE(-44.683,-44.683,-60.767,-60.767) |
geographic |
Canada Cow Head Green Point Broom Point Martin Point |
geographic_facet |
Canada Cow Head Green Point Broom Point Martin Point |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_source |
Geological Magazine volume 156, issue 5, page 759-771 ISSN 0016-7568 1469-5081 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s001675681800002x |
container_title |
Geological Magazine |
container_volume |
156 |
container_issue |
5 |
container_start_page |
759 |
op_container_end_page |
771 |
_version_ |
1802647064841027584 |