التفاصيل البيبلوغرافية
| العنوان: |
Carbonate uranium isotopes across Cretaceous OAE 2 in southern Mexico: New constraints on the global spread of marine anoxia and organic carbon burial |
| المؤلفون: |
Kulenguski, Joseph T., Gilleaudeau, Geoffrey J., Kaufman, Alan J., Kipp, Michael A., Tissot, François L. H., Goepfert, Tyler J., Pitts, Alan D., Pierantoni, Pietropaolo, Evans, Michael N., Elrick, Maya |
| المصدر: |
Palaeogeography, Palaeoclimatology, Palaeoecology, 628, 111756, (2023-10-15) |
| بيانات النشر: |
Elsevier |
| سنة النشر: |
2023 |
| المجموعة: |
Caltech Authors (California Institute of Technology) |
| مصطلحات موضوعية: |
Paleontology, Earth-Surface Processes, Ecology, Evolution, Behavior and Systematics, Oceanography |
| الوصف: |
Oceanic anoxic events (OAEs) represent discrete intervals of decreased marine oxygen concentrations often associated withvolcanism, enhancedorganic carbonburial coupled with positive δ13C excursions, and significant biotic turnover. Cretaceous OAE 2 (ca. 94 Mya) is especially notable for globally-distributed changes in calcareous invertebrate and plankton populations. While the presence of organic-rich facies is consistent with locally anoxic environments in many cases, determining the global extent of anoxia is more problematic. To address this issue, we investigateuranium isotope(δ238U) compositions ofupper Cretaceous(Cenomanian-Turonian) open marineplatform carbonatesfrom southernMexicoas a proxy for global seawaterredox conditions. These data are complementary to previous δ238U studies across OAE 2 in bothblack shalesand pelagic carbonates, which have yielded variable results that reflect both global redox and localdepositional processes. In Morelos Formation carbonates, a significant and well-defined negative δ238U excursion down to a nadir of −0.6‰ is recorded over an ∼40m interval. This is consistent with the expansion of marine anoxia, pointing to an areal extent of anoxic seawater of about 1–10% of the global seafloor (or∼5 to 50 times the modern value). Importantly, based on biostratigraphically-controlled estimates of sediment accumulation rates, the δ238U anomaly precedes the δ13C excursion by a median of ∼45 to 51 kyr (95th percentile confidence interval, CI) or∼105 to 120 kyr (95th percentile CI) depending on how the onset of the δ238U anomaly is estimated. These results, along with previously reported thallium isotope and trace metal data, suggest that anoxic expansion precededcarbon cycle perturbation. This observation further increases estimates of the duration of OAE 2, implying that widespread ocean anoxia may have lasted >900 kyr. ; © 2023 Elsevier. ; We thank theAmerican Association of Petroleum Geologists(AAPG) and theGeorge Mason UniversityCollege of Science for funding this project. ... |
| نوع الوثيقة: |
article in journal/newspaper |
| اللغة: |
English |
| Relation: |
https://ars.els-cdn.com/content/image/1-s2.0-S0031018223003747-mmc1.xlsx; https://doi.org/10.1016/j.palaeo.2023.111756 |
| DOI: |
10.1016/j.palaeo.2023.111756 |
| الاتاحة: |
https://doi.org/10.1016/j.palaeo.2023.111756 |
| Rights: |
info:eu-repo/semantics/openAccess ; No commercial reproduction, distribution, display or performance rights in this work are provided. |
| رقم الانضمام: |
edsbas.57A3C126 |
| قاعدة البيانات: |
BASE |