2.4-Myr eccentricity node; Monte Carlo simulation; Silurian; wavelet; WaverideR package; δ13C excursion; Earth and Planetary Sciences (all)
Abstract :
[en] The type-Silurian Cellon section in the Carnic Alps in Austria underpins much of the current Silurian conodont zonations, forming the basis for the Silurian timescale. However, the Silurian record of the Cellon section lacks radiometric and astrochronological age constraints, making it difficult to gain insights into the processes pacing Silurian (anoxic) events. To attain age constraints and investigate the pacing Silurian (anoxic) events by astronomical cycles, a cyclostratigraphic study was conducted on high-resolution pXRF (CaO, Al2O3, and Fe2O3) and induration records spanning the Ludlow and Pridoli parts of the Cellon section. Astronomical cycles ranging from precession to the 405-kyr eccentricity cycle were first recognised visually in the field and in proxy records. The visual detection of astronomical cycles served as an input for the WaverideR R package, enabling the tracking of the 405-kyr eccentricity period in each proxy’s continous wavelet transform scalograms. These tracked period curves were combined with external age controls through multiple Monte Carlo simulations, generating an (absolute) age model. This age model is used to assign ages and durations and their respective uncertainties to a hiatus in the Ludfordian, conodont zones, lithological units, geochronological units and events, yielding new ages for Silurian stage boundaries (e.g., Gorstian-Ludfordian boundary at 425.92 ± 0.65 Ma, the Ludfordian-Pridoli boundary at 423.03 ± 0.53 Ma, the Silurian-Devonian boundary at 418.86 ± 1.02 Ma), and new durations for the Ludfordian at 2.89 ± 0.35 Myr and Pridoli at 4.24 ± 0.46 Myr. Furthermore, the imprint of astronomical cycles in the Cellon section itself indicates that the Linde, Klev and Silurian-Devonian boundary events all occur after a 2.4-Myr eccentricity node, indicating pacing by astronomical forcing, similar to other Devonian and Cretaceous anoxic events. The Lau event, however, does not appear to coincide with a 2.4-Myr eccentricity node.
Corradini, Carlo; Dipartimento di Matematica e Geoscienze, Università di Trieste, Trieste, Italy
Pondrelli, Monica; International Research School of Planetary Sciences, Pescara, Italy ; Dipartimento di Ingegneria e Geologia, Università d’Annunzio, Pescara, Italy
Pas, Damien ; Université de Liège - ULiège > Département de géologie > Pétrologie sédimentaire ; Institute of Earth Sciences (ISTE), University of Lausanne, Lausanne, Switzerland
MA is financially supported by the FNRS-PDR T.0051.19 grant. A-CD acknowledges the \u201CConseil Universitaire de la recherche et la valorisation,\u201D as well as \u201CSubside F\u00E9d\u00E9ral de la recherche\u201D for financial support for the acquisition of the Portable XRF Bruker Tracer 5G, as well as National Science Foundation grant (J.0037.21, T.0037.22, and R.5541-J-F-B). CC acknowledges the Italian Ministry of University and Research Project 2022ZH5RWP, PRIN 2022 \u201CDEEP PAST.\u201D DP acknowledges the Swiss National Science Foundation grant PZ00P2-193520.The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. The FNRS-PDR T.0051.19 grant supported MA. A-CD was supported by the \u201CConseil Universitaire de la recherche et la valorisation,\u201D as well as \u201CSubside F\u00E9d\u00E9ral de la recherche\u201D for financial support for the acquisition of the Portable XRF Bruker Tracer 5G, as well as National Science Foundation grant (J.0037.21, T.0037.22, and R.5541-J-F-B). CC was supported by the Italian Ministry of University and Research Project 2022ZH5RWP, PRIN 2022 \u201CDEEP PAST\u201D. The Swiss National Science Foundation supported DP with grant PZ00P2-193520.
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