Astronomical time scale for the Paleozoic Era

Milankovitch cycles are quasi-periodic fluctuations in insolation forced by variations in the Earth's astronomical parameters, inducing climate change, and in turn affecting sedimentation and the formation of cyclostratigraphy. Astronomical calibration of the cyclostratigraphy can be exploited as a high-resolution (0.02–0.4 Myr) astronomical time scale (ATS), facilitating the reconstruction of Earth's evolutionary history. The ATS is already an important geochronometer for the Cenozoic and Mesozoic eras, however, the ATS for the Paleozoic Era has yet to be fully constructed. Radioisotopic age-calibrated Milankovitch cycles have been detected in Paleozoic strata, linked to the hierarchy of sedimentary cycles deposited in the continental, paralic, and marine environments. The orbital eccentricity metronome (i.e., 405-kyr cycle) has already been used to construct the ATS for the timing of Paleozoic geological and climatic events. Here, we review Paleozoic cyclostratigraphy and develop a provisional ATS from published paleoclimatic proxy time series, which results in revisions to the timing of key geological events in the Paleozoic Era.