405,000 year cycle in Earth Eccentricity found in 215 million years of climate

First published: 2020

Brief summary

CRI blog post discussing a PNAS paper on the 405,000-year eccentricity cycle as a stable climate-paced geological signal.

Article

One of the four main Milankovitch cycles is a 405,000 year fluctuation in the Earth’s orbital eccentricity. This means that the Earth’s orbit gets more and less circular over that period, affecting the extremes of climate. The variation is due to the effects of Jupiter and Venus which are the two planets with the greatest tidal effect.

https://www.pnas.org/content/115/24/6153

“Rhythmic climate cycles of various assumed frequencies recorded in sedimentary archives are increasingly used to construct a continuous geologic timescale. However, the age range of valid theoretical orbital solutions is limited to only the past 50 million years.

New U–Pb zircon dates from the Chinle Formation tied using magnetostratigraphy to the Newark–Hartford astrochronostratigraphic polarity timescale provide empirical confirmation that the unimodal 405-kiloyear orbital eccentricity cycle reliably paces Earth’s climate back to at least 215 million years ago, well back in the Late Triassic Period.”

Additional summary

The remainder quotes and discusses the Newark–Hartford astrochronostratigraphic polarity timescale and the role of the stable 405-kyr eccentricity cycle in geological and climate calibration.

Source details and credits

• Source / publisher: CRI Blog / Ray Tomes
• Source type: Blog post
• URL type: WWW
• Credits: CRI Blog / Ray Tomes
• URL: https://cyclesresearchinstitute.wordpress.com/2020/04/03/405000-year-cycle-in-earth-eccentricity-found-in-215-million-years-of-climate/