Dear WeatherCat readers of weather-related news,
Google news reported an amazing claim: that the combined orbits of Jupiter and Venus create another stable cycle on the earth's climate that occurs every 405,000 years. The abstract of the paper can be found on the Proceedings of the National Academy of Sciences of the United States of America website:
http://www.pnas.org/content/early/2018/05/01/1800891115It is heavy stuff. Here is the key point in the significance section:
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.
The methodology they use is described here in another heavy-duty bit of text:
To test the validity of the dangling APTS and orbital periodicities, we recovered a diagnostic magnetic polarity sequence in the volcaniclastic-bearing Chinle Formation in a scientific drill core from Petrified Forest National Park (Arizona) that provides an unambiguous correlation to the APTS. New high precision U?Pb detrital zircon dates from the core are indistinguishable from ages predicted by the APTS back to 215 million years before present. The agreement shows that the APTS is continuous and supports a stable 405-kiloyear cycle well beyond theoretical solutions. The validated Newark?Hartford APTS can be used as a robust framework to help differentiate provinciality from global temporal patterns in the ecological rise of early dinosaurs in the Late Triassic, amongst other problems.
There is a Wikipedia article on the mechanism by which the authors were able to date the sediments:
https://en.wikipedia.org/wiki/Detrital_zircon_geochronologyHowever, that doesn't explain how they were able to confirm the climatic effects of the cycle. Hopefully some additional articles will come out with a translation for those of us who are proudly:
"Just plain folks!" Stay tuned!
Cheers, Edouard