Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada
In this study, strontium-, carbon- and oxygen-isotope data are reported from Early Jurassic belemnites from Yakoun River, Queen Charlotte Islands (QCI), British Columbia. Assuming that the established ammonite correlations between Canada and Europe are accurate, the seawater 87Sr/86Sr curve between...
| Main Authors: | , , |
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| Format: | Journal article |
| Language: | English |
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2007
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| _version_ | 1826298535985807360 |
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| author | Grocke, DR Hesselbo, S Findlay, D |
| author_facet | Grocke, DR Hesselbo, S Findlay, D |
| author_sort | Grocke, DR |
| collection | OXFORD |
| description | In this study, strontium-, carbon- and oxygen-isotope data are reported from Early Jurassic belemnites from Yakoun River, Queen Charlotte Islands (QCI), British Columbia. Assuming that the established ammonite correlations between Canada and Europe are accurate, the seawater 87Sr/86Sr curve between Europe and QCI should be similar. However, the Rarenodia planulata and Phymatoceras crassicosta ammonite biozones from Yakoun River record 87Sr/86Sr values that are lower than expected. This shift is interpreted to be a result of diagenetic alteration by later hydrothermal fluid (87Sr-depleted). In general, the diagenetic samples have more negative δ13Cbel and δ18Obel values, and higher Mn concentrations, but show no difference in Fe concentration. A δ13Cbel curve from diagenetically screened samples exhibits only slightly depleted values with respect to a similar curve generated from Europe. A similar curve for δ18Obel shows a striking similarity with that generated from Europe. This study illustrates that diagenetic effects on Sr-isotope composition can lower values from the expected seawater 87Sr/86Sr curve, thus potentially producing erroneous correlations between ammonite biostratigraphic schemes. Traditional screening methods for diagenesis, such as cathodoluminescence and trace-element abundances, were inadequate for evaluating diagenesis in the Yakoun River sections. Other such studies must also consider alternative and (or) a combination of methods in evaluating geochemical data from belemnites. © 2007 NRC Canada. |
| first_indexed | 2024-03-07T04:48:21Z |
| format | Journal article |
| id | oxford-uuid:d415d489-d591-4e74-9f1c-27cc43ac49c9 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T04:48:21Z |
| publishDate | 2007 |
| record_format | dspace |
| spelling | oxford-uuid:d415d489-d591-4e74-9f1c-27cc43ac49c92022-03-27T08:15:56ZAtypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, CanadaJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d415d489-d591-4e74-9f1c-27cc43ac49c9EnglishSymplectic Elements at Oxford2007Grocke, DRHesselbo, SFindlay, DIn this study, strontium-, carbon- and oxygen-isotope data are reported from Early Jurassic belemnites from Yakoun River, Queen Charlotte Islands (QCI), British Columbia. Assuming that the established ammonite correlations between Canada and Europe are accurate, the seawater 87Sr/86Sr curve between Europe and QCI should be similar. However, the Rarenodia planulata and Phymatoceras crassicosta ammonite biozones from Yakoun River record 87Sr/86Sr values that are lower than expected. This shift is interpreted to be a result of diagenetic alteration by later hydrothermal fluid (87Sr-depleted). In general, the diagenetic samples have more negative δ13Cbel and δ18Obel values, and higher Mn concentrations, but show no difference in Fe concentration. A δ13Cbel curve from diagenetically screened samples exhibits only slightly depleted values with respect to a similar curve generated from Europe. A similar curve for δ18Obel shows a striking similarity with that generated from Europe. This study illustrates that diagenetic effects on Sr-isotope composition can lower values from the expected seawater 87Sr/86Sr curve, thus potentially producing erroneous correlations between ammonite biostratigraphic schemes. Traditional screening methods for diagenesis, such as cathodoluminescence and trace-element abundances, were inadequate for evaluating diagenesis in the Yakoun River sections. Other such studies must also consider alternative and (or) a combination of methods in evaluating geochemical data from belemnites. © 2007 NRC Canada. |
| spellingShingle | Grocke, DR Hesselbo, S Findlay, D Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada |
| title | Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada |
| title_full | Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada |
| title_fullStr | Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada |
| title_full_unstemmed | Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada |
| title_short | Atypical diagenetic effects on strontium-isotope composition of Early Jurassic belemnites, Queen Charlotte Islands, British Columbia, Canada |
| title_sort | atypical diagenetic effects on strontium isotope composition of early jurassic belemnites queen charlotte islands british columbia canada |
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