Geologic evidence for chaotic behavior of the planets and its constraints on the third-order eustatic sequences at the end of the Late Paleozoic Ice Age

• Published in: Palaeogeography, palaeoclimatology, palaeoecology Vol. 440; pp. 848 - 859
• Main Authors: Fang, Qiang, Wu, Huaichun, Hinnov, Linda A., Jing, Xiuchun, Wang, Xunlian, Jiang, Qingchun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.12.2015
• Subjects: Brackish; Late Paleozoic Ice Age; Long-period astronomical forcing; Maokou Formation; Marine; Milankovitch cycles; South China; Third-order eustatic sequence; China, People's Rep; PSE, Australia; Late Paleozoic Ice Age; South China; Milankovitch cycles; Third-order eustatic sequence; Long-period astronomical forcing; Maokou Formation
• ISSN: 0031-0182; 1872-616X
• DOI: 10.1016/j.palaeo.2015.10.014

High-resolution (948 samples) measurements of anhysteretic remanent magnetization (ARM) were performed on the ~200m thick Early–Middle Permian Maokou Formation of the Shangsi section, South China. The ARM variations are quasi-periodic and the wavelengths of significant cycles collectively present a ratio of 20:5:2:1 throughout the formation, corresponding to long orbital eccentricity, short orbital eccentricity, obliquity, and precession cycles. A strong obliquity (44 and 33kyr) signal suggests that waning and waxing of the ice sheet in eastern Australia at the end of the Late Paleozoic Ice Age (LPIA) exerted a significant influence on global climate and sea level. A “floating” astronomical time scale (ATS) is developed using the 405kyr orbital eccentricity cycle as an astronomical calibration target. This results in estimation of the Roadian and Wordian stages duration as 3.7±0.4myr and 2.9±0.4myr, respectively. Prominent ~2myr cycles likely originated from Earth and Mars secular frequencies g4–g3, and ~1myr cycles from s4–s3. These periodicities are shorter than those observed in the Cenozoic Era, which may be due to the chaotic behavior of the planets, but still reflecting 2:1 secular resonance between Earth and Mars. Third-order eustatic sequences are linked to the s4–s3 obliquity term, which suggests a glacioeustatic controlling mechanism during this transitional stage from Paleozoic icehouse to Mesozoic greenhouse. •Astronomically-calibrated time scale is estimated for Roadian and Wordian stages.•Modulation cycles of eccentricity and obliquity were shorter in the Middle Permian.•Modulation cycles of obliquity controlled third-order eustatic sequences.