2
$\begingroup$

These limestone-clay rocks are very common in the Alps, they come from weather changes.

How many years does it take to make one of the rock bands? 7 years, equivalent to an el-nino type event? 1000 years? 20,000 years?

enter image description here From the wiki page which is only in French: https://fr.wikipedia.org/wiki/Formation_marno-calcaire

Improve this question
$\endgroup$
1
  • 1
    $\begingroup$ upper Jurassic/lower Cretaceous, warm climate, flooded continental shelves, climate cycles from orbital parameters, Milankovic cycles. Here: probably ~40ky, maybe ~20ky. $\endgroup$
    – user20217
    May 25, 2020 at 8:07

1 Answer 1

Reset to default
2
$\begingroup$

The layers correspond to thousands of years, i.e. 23,000 years in the Danien timeline: enter image description here

The page sais that there is a variation of 23,000 for precession of the equinoxes and 100,000 for variation of ellipticity. https://planet-terre.ens-lyon.fr/image-de-la-semaine/Img421-2013-04-15.xml

Improve this answer
$\endgroup$
1

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.