Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in Cascadia
Abstract Holocene sea‐level reconstructions from tidal marshes are commonly derived from proxy indicators that have a consistent and quantifiable relationship with tidal elevation. While microfossils are most commonly employed, using multiple indicators leads to more robust reconstructions. We explo...
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Wiley
2025-05-01
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| Series: | Geochemistry, Geophysics, Geosystems |
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| Online Access: | https://doi.org/10.1029/2024GC012129 |
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| author | Anthony Giang Jessica E. Pilarczyk Isabel Hong Louise Riou David Huntley Roger MacLeod Owen G. Ward John J. Clague Peter Bobrowsky Andrea D. Hawkes Simon E. Engelhart Benjamin P. Horton |
| author_facet | Anthony Giang Jessica E. Pilarczyk Isabel Hong Louise Riou David Huntley Roger MacLeod Owen G. Ward John J. Clague Peter Bobrowsky Andrea D. Hawkes Simon E. Engelhart Benjamin P. Horton |
| author_sort | Anthony Giang |
| collection | DOAJ |
| description | Abstract Holocene sea‐level reconstructions from tidal marshes are commonly derived from proxy indicators that have a consistent and quantifiable relationship with tidal elevation. While microfossils are most commonly employed, using multiple indicators leads to more robust reconstructions. We explore the utility of elemental geochemistry obtained through x‐ray fluorescence as a proxy indicator in tidal marshes at Port Alberni, British Columbia, Canada and Willapa Bay, Washington, United States. The elemental composition of bulk surface sediment collected from 141 stations along 10 transects was determined using an ITRAX Core Scanner. Partitioning Around Medoids cluster analysis on the elemental data distinguished between tidal flat, low marsh, and high marsh zones at both locations, similar to zones established from previously published microfossil (foraminifera, diatoms) data sets on the same samples. The elemental composition of low elevation samples from the tidal flat is dominated by lithogenic (Si, K, Ti, Fe) and biogenic (Sr) elements, whereas higher elevation samples have high proportions of organic content (Br, incoherent and coherent scattering ratio). Principal Component Analysis points to differences in organic versus inorganic content, a function of tidal elevation, as the main driver of geochemistry‐derived zones. Approximately 70% of the elemental variability within both marshes is controlled by the inorganic content, as indicated by lithogenic and biogenic elements versus organic content. The elemental composition of bulk surface sediment from two regions spaced ∼300 km apart shows a promising relationship with tidal elevation over a wider spatial scale and highlights the potential of this proxy for use in sea‐level reconstructions. |
| format | Article |
| id | doaj-art-96007c1a74ff45218e6ff77cf2a01a2a |
| institution | Kabale University |
| issn | 1525-2027 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Wiley |
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| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj-art-96007c1a74ff45218e6ff77cf2a01a2a2025-08-20T03:25:27ZengWileyGeochemistry, Geophysics, Geosystems1525-20272025-05-01265n/an/a10.1029/2024GC012129Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in CascadiaAnthony Giang0Jessica E. Pilarczyk1Isabel Hong2Louise Riou3David Huntley4Roger MacLeod5Owen G. Ward6John J. Clague7Peter Bobrowsky8Andrea D. Hawkes9Simon E. Engelhart10Benjamin P. Horton11Department of Earth Sciences Simon Fraser University Burnaby BC CanadaDepartment of Earth Sciences Simon Fraser University Burnaby BC CanadaDepartment of Earth Sciences Simon Fraser University Burnaby BC CanadaDepartment of Earth Sciences Simon Fraser University Burnaby BC CanadaDepartment of Earth Sciences Simon Fraser University Burnaby BC CanadaGeological Survey of Canada Pacific Division Vancouver BC CanadaDepartment of Statistics and Actuarial Science Simon Fraser University Burnaby BC CanadaDepartment of Earth Sciences Simon Fraser University Burnaby BC CanadaGeological Survey of Canada Pacific Division Vancouver BC CanadaDepartment of Earth and Ocean Sciences University of North Carolina Wilmington NC USADepartment of Geography Durham University Durham UKCity University of Hong Kong Kowloon Tong Hong KongAbstract Holocene sea‐level reconstructions from tidal marshes are commonly derived from proxy indicators that have a consistent and quantifiable relationship with tidal elevation. While microfossils are most commonly employed, using multiple indicators leads to more robust reconstructions. We explore the utility of elemental geochemistry obtained through x‐ray fluorescence as a proxy indicator in tidal marshes at Port Alberni, British Columbia, Canada and Willapa Bay, Washington, United States. The elemental composition of bulk surface sediment collected from 141 stations along 10 transects was determined using an ITRAX Core Scanner. Partitioning Around Medoids cluster analysis on the elemental data distinguished between tidal flat, low marsh, and high marsh zones at both locations, similar to zones established from previously published microfossil (foraminifera, diatoms) data sets on the same samples. The elemental composition of low elevation samples from the tidal flat is dominated by lithogenic (Si, K, Ti, Fe) and biogenic (Sr) elements, whereas higher elevation samples have high proportions of organic content (Br, incoherent and coherent scattering ratio). Principal Component Analysis points to differences in organic versus inorganic content, a function of tidal elevation, as the main driver of geochemistry‐derived zones. Approximately 70% of the elemental variability within both marshes is controlled by the inorganic content, as indicated by lithogenic and biogenic elements versus organic content. The elemental composition of bulk surface sediment from two regions spaced ∼300 km apart shows a promising relationship with tidal elevation over a wider spatial scale and highlights the potential of this proxy for use in sea‐level reconstructions.https://doi.org/10.1029/2024GC012129CascadiaX‐ray fluorescencetidal marshsurface transectsea‐level changemicropaleontology |
| spellingShingle | Anthony Giang Jessica E. Pilarczyk Isabel Hong Louise Riou David Huntley Roger MacLeod Owen G. Ward John J. Clague Peter Bobrowsky Andrea D. Hawkes Simon E. Engelhart Benjamin P. Horton Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in Cascadia Geochemistry, Geophysics, Geosystems Cascadia X‐ray fluorescence tidal marsh surface transect sea‐level change micropaleontology |
| title | Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in Cascadia |
| title_full | Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in Cascadia |
| title_fullStr | Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in Cascadia |
| title_full_unstemmed | Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in Cascadia |
| title_short | Elemental Geochemistry of Tidal Marsh Sediment and Its Potential as an Indicator of Sea‐Level Change in Cascadia |
| title_sort | elemental geochemistry of tidal marsh sediment and its potential as an indicator of sea level change in cascadia |
| topic | Cascadia X‐ray fluorescence tidal marsh surface transect sea‐level change micropaleontology |
| url | https://doi.org/10.1029/2024GC012129 |
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