Astronomical time scale for the Paleozoic Era

Milankovitch cycles are quasi-periodic fluctuations in insolation forced by the variation in Earth's astronomical parameters. The astronomically induced climate change affected the sedimentation processes which led to the formation of rhythmic records in rocks. Astronomical calibration of these cycles can be exploited as the 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, that 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 the Paleozoic cyclostratigraphy and develop a provisional ATS from the published paleoclimatic proxy time series, which results in revisions to the timing of key geological events in the Paleozoic Era.