Orbitally-paced climate change in the early Cambrian and its implications for the history of the Solar System
Zhang, T.; Li, Y.; Fan, T.; da Silva, A.-C.; Shi, J.; Gao, Q.; Kuang, M.; Liu, W.; Gao, Z.; Li, M. (2022). Orbitally-paced climate change in the early Cambrian and its implications for the history of the Solar System. Earth Planet. Sci. Lett. 583: 117420. https://dx.doi.org/10.1016/j.epsl.2022.117420
In: Earth and Planetary Science Letters. Elsevier: Amsterdam. ISSN 0012-821X; e-ISSN 1385-013X, meer
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| Author keywords |
Cyclostratigraphy; sedimentary noise; Earth-Moon system evolution; Earth-Mars secular resonance; sea level; Stage 2-Stage 3 |
| Auteurs | | Top |
- Zhang, T.
- Li, Y.
- Fan, T.
- da Silva, A.-C., meer
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- Shi, J.
- Gao, Q.
- Kuang, M.
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| Abstract |
The early Cambrian was a critical period of Earth history, marked by explosive diversification of metazoans and several profound changes in Earth's surface environments and global climate. A valid temporal framework for the early Cambrian Period and across the major bio-events is poorly constrained, and the key underlying forcings of million-year (Myr) scale sea-level variations in a greenhouse lacking polar ice sheets are still disputed. Here, the high-resolution gamma-ray logs (GR) and Fe/Al records are utilized to conduct cyclostratigraphic analysis of the early Cambrian Stage 2-Stage 3 Qiongzhusi Formation of the Well A borehole in South China. A ∼10.8 Myr-long high-resolution astronomical time scale across Stage 2-Stage 3 is developed by astronomical tuning of gamma-ray logs and Fe/Al series to the stable 405-kyr long-eccentricity cycles. The Myr-scale sea-level fluctuations in the early Cambrian greenhouse are reconstructed through the sedimentary noise modeling of the 405-tuned GR series and agree with sequence stratigraphic interpretations, lithofacies stacking patterns, and depositional environment changes. The antiphase correlation of filtered ∼1.5 Myr cycles of sedimentary noise curves with the ∼1.5 Myr obliquity modulation cycles demonstrates that the variations in land-ocean water exchange linked to changes in poleward moisture and heat transport dominated by ∼1.5 Myr obliquity modulation cycles may be a primary driver for eustasy during non-glacial early Cambrian period. A new resonance state in the early Cambrian Stage 2-Stage 3, manifested by ∼1.5 Myr eccentricity: ∼1.5 Myr obliquity, could be mainly associated with the Earth-Mars secular resonance and constrain the chaotic evolution of the Solar System in deep time. Two independent approaches are employed to reconstruct the history of Earth-Moon system characteristics, including the precession constant, the Earth-Moon distance and the day length. Our results enhance knowledge of the connection of Myr-scale sea-level variations to astronomically induced climate change under greenhouse climate and provide new empirical constraints on the chaotic motion of the Solar System and the evolution of the Earth-Moon System in deep time. |
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