Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space
Abstract Continental interiors were flooded by epeiric seas during many intervals of the geologic past. Few modern analogs exist for these environments, however, and basic variables such as redox, salinity, and restriction are difficult to reconstruct in deep time. Despite these challenges, constrai...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2023-08-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2023GC010973 |
| _version_ | 1797638070620651520 |
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| author | Geoffrey J. Gilleaudeau Wei Wei Mariano N. Remírez Yi Song Timothy W. Lyons Steven Bates Ariel D. Anbar Thomas J. Algeo |
| author_facet | Geoffrey J. Gilleaudeau Wei Wei Mariano N. Remírez Yi Song Timothy W. Lyons Steven Bates Ariel D. Anbar Thomas J. Algeo |
| author_sort | Geoffrey J. Gilleaudeau |
| collection | DOAJ |
| description | Abstract Continental interiors were flooded by epeiric seas during many intervals of the geologic past. Few modern analogs exist for these environments, however, and basic variables such as redox, salinity, and restriction are difficult to reconstruct in deep time. Despite these challenges, constraining epeiric watermass properties is critical because much of our preserved and accessible sedimentary record was deposited in such settings. Here, we present a four‐dimensional reconstruction of watermass evolution in the Late Devonian Appalachian Seaway of North America. We use combined proxies for sediment supply, paleosalinity, paleoredox, and basin hydrography in six cores through the Upper Devonian Cleveland Shale deposited across a paleo‐depth transect. Cyclic, coupled changes in sedimentation, redox, and salinity are recorded in environments near the Catskill Delta. Additionally, a pronounced salinity gradient was present from low‐brackish conditions near the delta to fully marine conditions in the basin interior, with a lower‐salinity mixing zone recorded across the Cumberland Sill. We also identified two broad sequences—the lower and upper Cleveland Shale—each of which shows distinct watermass signatures. The lower Cleveland Shale records a redox gradient with euxinia only present along the Cumberland Sill, whereas the upper Cleveland Shale records intensification of euxinia (potentially in the photic zone) at all six sites, which may be coincident with the Hangenberg extinction event. Ultimately, this study identifies pronounced epeiric watermass gradients over short timescales (millennia) and distances (hundreds of km or less), highlighting the need for interpreting the geochemistry of epicontinental deposits in the context of basin hydrography and paleosalinity. |
| first_indexed | 2024-03-11T12:57:24Z |
| format | Article |
| id | doaj.art-46e58af5bcb2434389e055cfbd7795ff |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:57:24Z |
| publishDate | 2023-08-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-46e58af5bcb2434389e055cfbd7795ff2023-11-03T16:56:03ZengWileyGeochemistry, Geophysics, Geosystems1525-20272023-08-01248n/an/a10.1029/2023GC010973Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and SpaceGeoffrey J. Gilleaudeau0Wei Wei1Mariano N. Remírez2Yi Song3Timothy W. Lyons4Steven Bates5Ariel D. Anbar6Thomas J. Algeo7Department of Atmospheric, Oceanic, and Earth Sciences George Mason University VA Fairfax USAState Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan ChinaDepartment of Atmospheric, Oceanic, and Earth Sciences George Mason University VA Fairfax USASchool of Marine Sciences Guangxi University Nanning ChinaDepartment of Earth and Planetary Sciences University of California CA Riverside USADepartment of Earth and Planetary Sciences University of California CA Riverside USASchool of Earth and Space Exploration Arizona State University AZ Tempe USAState Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan ChinaAbstract Continental interiors were flooded by epeiric seas during many intervals of the geologic past. Few modern analogs exist for these environments, however, and basic variables such as redox, salinity, and restriction are difficult to reconstruct in deep time. Despite these challenges, constraining epeiric watermass properties is critical because much of our preserved and accessible sedimentary record was deposited in such settings. Here, we present a four‐dimensional reconstruction of watermass evolution in the Late Devonian Appalachian Seaway of North America. We use combined proxies for sediment supply, paleosalinity, paleoredox, and basin hydrography in six cores through the Upper Devonian Cleveland Shale deposited across a paleo‐depth transect. Cyclic, coupled changes in sedimentation, redox, and salinity are recorded in environments near the Catskill Delta. Additionally, a pronounced salinity gradient was present from low‐brackish conditions near the delta to fully marine conditions in the basin interior, with a lower‐salinity mixing zone recorded across the Cumberland Sill. We also identified two broad sequences—the lower and upper Cleveland Shale—each of which shows distinct watermass signatures. The lower Cleveland Shale records a redox gradient with euxinia only present along the Cumberland Sill, whereas the upper Cleveland Shale records intensification of euxinia (potentially in the photic zone) at all six sites, which may be coincident with the Hangenberg extinction event. Ultimately, this study identifies pronounced epeiric watermass gradients over short timescales (millennia) and distances (hundreds of km or less), highlighting the need for interpreting the geochemistry of epicontinental deposits in the context of basin hydrography and paleosalinity.https://doi.org/10.1029/2023GC010973Cleveland ShaleFamennianeuxiniairon speciationtrace metalspaleosalinity |
| spellingShingle | Geoffrey J. Gilleaudeau Wei Wei Mariano N. Remírez Yi Song Timothy W. Lyons Steven Bates Ariel D. Anbar Thomas J. Algeo Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space Geochemistry, Geophysics, Geosystems Cleveland Shale Famennian euxinia iron speciation trace metals paleosalinity |
| title | Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space |
| title_full | Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space |
| title_fullStr | Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space |
| title_full_unstemmed | Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space |
| title_short | Geochemical and Hydrographic Evolution of the Late Devonian Appalachian Seaway: Linking Sedimentation, Redox, and Salinity Across Time and Space |
| title_sort | geochemical and hydrographic evolution of the late devonian appalachian seaway linking sedimentation redox and salinity across time and space |
| topic | Cleveland Shale Famennian euxinia iron speciation trace metals paleosalinity |
| url | https://doi.org/10.1029/2023GC010973 |
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