Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic)
Molybdenum (Mo)-isotope chemostratigraphy of organic-rich mudrocks has been a valuable tool for testing the hypothesis that the Toarcian Oceanic Anoxic Event (T-OAE, Early Jurassic, ~183 Ma) was characterized by the spread of marine euxinia (and organic-matter burial) at a global scale. However, the...
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| Format: | Journal article |
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American Geophysical Union
2017
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| _version_ | 1797057659070840832 |
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| author | Dickson, A Gill, B Ruhl, M Jenkyns, H Porcelli, D Idiz, E Lyons, T van den Boorn, S |
| author_facet | Dickson, A Gill, B Ruhl, M Jenkyns, H Porcelli, D Idiz, E Lyons, T van den Boorn, S |
| author_sort | Dickson, A |
| collection | OXFORD |
| description | Molybdenum (Mo)-isotope chemostratigraphy of organic-rich mudrocks has been a valuable tool for testing the hypothesis that the Toarcian Oceanic Anoxic Event (T-OAE, Early Jurassic, ~183 Ma) was characterized by the spread of marine euxinia (and organic-matter burial) at a global scale. However, the interpretation of existing Mo-isotope data for the T-OAE (from Yorkshire, Cleveland Basin, U.K.) is equivocal. In this study, three new Mo-isotope profiles are presented: from Dotternhausen Quarry (South German Basin, Germany), the Rijswijk core (West Netherlands Basin, Netherlands) and the Dogna core (Belluno Basin, northern Italy). Precise bio- and chemo34 stratigraphic correlation between the three sites allows a direct comparison of the data, enabling some key conclusions to be reached: (i) The Mo-isotope composition of seawater during the peak of the T-OAE was probably close to ~1.45 ‰, implicating a greater removal flux of sulphides from seawater, and a larger extent of global seafloor euxinia compared to the present day; (ii) Moisotope cycles previously identified in the Yorkshire sedimentary succession are attributed to changes in the degree of local 39 Mo drawdown from overlying Cleveland Basin seawater; (iii) The consistency of the new multi-site Mo-isotope dataset indicates a secular reduction in the burial of sulphides globally in the late stages of the T-OAE, implying a contraction in the extent of global marine euxinia; (iv) Subtle differences in the Mo-isotope composition of deposits formed in different euxinic sub-basins of the European epicontinental shelf were probably governed by local variations in basin hydrography and rates of water renewal |
| first_indexed | 2024-03-06T19:39:32Z |
| format | Journal article |
| id | oxford-uuid:2032bbb2-12df-4d83-956c-1110d388af55 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T19:39:32Z |
| publishDate | 2017 |
| publisher | American Geophysical Union |
| record_format | dspace |
| spelling | oxford-uuid:2032bbb2-12df-4d83-956c-1110d388af552022-03-26T11:26:07ZMolybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic)Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2032bbb2-12df-4d83-956c-1110d388af55Symplectic Elements at OxfordAmerican Geophysical Union2017Dickson, AGill, BRuhl, MJenkyns, HPorcelli, DIdiz, ELyons, Tvan den Boorn, SMolybdenum (Mo)-isotope chemostratigraphy of organic-rich mudrocks has been a valuable tool for testing the hypothesis that the Toarcian Oceanic Anoxic Event (T-OAE, Early Jurassic, ~183 Ma) was characterized by the spread of marine euxinia (and organic-matter burial) at a global scale. However, the interpretation of existing Mo-isotope data for the T-OAE (from Yorkshire, Cleveland Basin, U.K.) is equivocal. In this study, three new Mo-isotope profiles are presented: from Dotternhausen Quarry (South German Basin, Germany), the Rijswijk core (West Netherlands Basin, Netherlands) and the Dogna core (Belluno Basin, northern Italy). Precise bio- and chemo34 stratigraphic correlation between the three sites allows a direct comparison of the data, enabling some key conclusions to be reached: (i) The Mo-isotope composition of seawater during the peak of the T-OAE was probably close to ~1.45 ‰, implicating a greater removal flux of sulphides from seawater, and a larger extent of global seafloor euxinia compared to the present day; (ii) Moisotope cycles previously identified in the Yorkshire sedimentary succession are attributed to changes in the degree of local 39 Mo drawdown from overlying Cleveland Basin seawater; (iii) The consistency of the new multi-site Mo-isotope dataset indicates a secular reduction in the burial of sulphides globally in the late stages of the T-OAE, implying a contraction in the extent of global marine euxinia; (iv) Subtle differences in the Mo-isotope composition of deposits formed in different euxinic sub-basins of the European epicontinental shelf were probably governed by local variations in basin hydrography and rates of water renewal |
| spellingShingle | Dickson, A Gill, B Ruhl, M Jenkyns, H Porcelli, D Idiz, E Lyons, T van den Boorn, S Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic) |
| title | Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic) |
| title_full | Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic) |
| title_fullStr | Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic) |
| title_full_unstemmed | Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic) |
| title_short | Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic) |
| title_sort | molybdenum isotope chemostratigraphy and paleoceanography of the toarcian oceanic anoxic event early jurassic |
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