Geologically constrained astronomical solutions for the Cenozoic era
Geologically constrained astronomical solutions for the Cenozoic era
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DOI：
10.1016/j.epsl.2022.117595
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发表时间：
2022-08
影响因子：
5.3
通讯作者：
R. Zeebe;L. Lourens
中科院分区：
文献类型：
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作者：
R. Zeebe;L. Lourens
天文学的解决方案提供了深入了解太阳系的动力学演化，是必不可少的工具，在循环地层学和天体年代学。迄今为止，建立一个绝对的、完全校准的天文时标（ATS）一直受到阻碍，因为由于太阳系的混乱，轨道计算在250 Ma之前不一致。我们最近开发了一种新的方法，可以将完全校准的天文时间尺度扩展到158 Ma。在这里，我们提出了地质数据和新的天文解决方案，将我们的方法扩展到整个古新世时代（2066年至2056年）。新的天文解决方案产生的数值太阳系积分后，我们的早期工作，现在提供地质约束的新生代（66-0马）的天文解决方案。轨道解可用于300 Ma -然而，我们警告说，由于太阳系中的动力学混沌，300-66 Ma的时间间隔是不受约束的。我们已经测试了我们的新解决方案的各种参数，包括数值步长，太阳四极矩，包括小行星的数量，初始位置和潮汐耗散的敏感性。我们证明，我们的新的解决方案产生改进的协议与整个古新世时代的地质记录相比，以前可用的天文解决方案的这一时期。此外，我们讨论了我们的结果对太阳系混沌和共振跃迁的影响。我们还获得了K/T边界（KTB）年龄的基础上，我们的新的解决方案，这表明稍微年轻的KTB年龄比那些推断从最新的40 Ar/39 Ar放射性测年。
Astronomical solutions provide insight into the Solar System's dynamical evolution and are indispensable tools in cyclostratigraphy and astrochronology. Constructing an absolute, fully calibrated astronomical time scale (ATS) has hitherto been hindered beyond ∼50 Ma because orbital calculations disagree before that age due to solar system chaos. We have recently developed a new approach that allows extending the fully calibrated astronomical time scale to ∼58 Ma. Here, we present geologic data and new astronomical solutions, extending our approach across the Paleocene epoch (∼66 to ∼56 Ma). New astronomical solutions were generated using numerical solar system integrations following our earlier work, which now provides geologically constrained astronomical solutions for the Cenozoic era (66-0 Ma). The orbital solutions are available to 300 Ma — we caution, however, that the time interval 300-66 Ma is unconstrained due to dynamical chaos in the solar system. We have tested the sensitivity of our new solutions to various parameters, including numerical stepsize, solar quadrupole moment, number of asteroids included, initial positions, and tidal dissipation. We demonstrate that our new solutions yield improved agreement with the geologic record across the Paleocene epoch, compared to previously available astronomical solutions for that period. Furthermore, we discuss implications of our results for solar system chaos and resonance transitions. We have also obtained K/T boundary (KTB) ages based on our new solutions, which suggest slightly younger KTB ages than those inferred from most recent40Ar/39Ar radiometric dating.