Astronomical recalibration of the Upper Triassic in St. Audrie's Bay and its implication for chaotic behavior in the solar system
Abstract
Astrochronology has become a powerful tool for refining geochronological frameworks and providing insights into paleoclimate forcing, basin evolution, etc. Nowadays time calibration of astrochronology, involving numerous statistical methods, requires robustness and consistency to improve reproducibility in cyclostratigraphy. However, the continuity and completeness of terrestrial successions can challenge the accuracy of astronomical calibrations, hindering global correlation and our understanding of palaeoclimate change. Here, we recalibrate the astronomical time scale (ATS) of the Late Triassic lacustrine stratigraphy in St. Audrie's Bay (UK) using recently proposed statistical tuning approaches. Compared with the previous short-eccentricity tuned ATS (Kemp and Coe, 2007), our new long-eccentricity tuned astrochronology indicates a longer duration (4.6 Myr vs. 3.7 Myr). The sedimentation rate based on 405-kyr tuning has the lowest root mean square error of all tuning options, suggesting that flawless recognition of 100-kyr eccentricity cycles throughout deep-time terrestrial records could be challenging due to the subjective assessment or the short multiple gaps. The 405-kyr cycle-calibrated magnetostratigraphy of the Upper Triassic in St. Audrie's Bay compares well with the 405-kyr cycle-calibrated magnetostratigraphy of the Newark Supergroup. Long-term cyclicities with a significant period of ∼2-Myr from tuned rock color series are in phase with that of Newark Supergroup. This supports our recalibrated ATS and further demonstrates the chaotic behavior of the solar system during the Late Triassic. Similar lake-level fluctuations reconstructed by sedimentary noise modeling between two successions also reveal the in-phase response to hydrologic changes in the arid belt. Our findings thus emphasize the importance of an integrated stratigraphic approach for precise global correlation of geological records.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFMPP11C..08W